IX. (SOLIDUNGULA)…

IX. (SOLIDUNGULA)

It will naturally be expected that I should give a full account of the parasites of the solipedal, solidungulate, or equine mammals. As regards the horse I regret that I cannot meet this expectation in so complete a manner as the subject deserves; nevertheless, with the aid of an extended bibliography the summary here offered will be found to be tolerably exhaustive. At all events I think I may say that no similar record has hitherto been attempted.

The liver fluke (Fasciola hepatica), though not very frequent in the horse, is not uncommon in the ass. In dissecting-room subjects at the Royal Veterinary College it is often encountered. In France it was originally found in the horse by Daubenton. As I learn from Sonsino, Dr. Abbate Bey recently recorded a similar find at Cairo. In solipeds generally the liver fluke appears to be almost harmless, for, notwithstanding the frightful ravages produced by rot amongst a variety of animals besides sheep, we have no evidence of the destruction of horses from this cause. In the German outbreak of 1663-65 multitudes of cattle and deer perished, and in the French outbreak of 1829-30 five thousand horned beasts succumbed in the arrondissement of Montmédy alone. In neither of these epizoötics were the solipeds affected. More importance attaches itself to the study of the amphistomatoid flukes. These parasites, though in a scientific sense only recently discovered in equine bearers, have been long known to the natives of India. They appear to be capable of producing serious intestinal irritation. I have described two forms (Amphistoma Collinsii and A. Coll., var. Stanleyi), which infest the colon. The specimens sent to Prof. Simonds from India by Mr Stanley, V.S., were much larger than those sent to me from Simla by Mr Collins, V.S., some ten years later (1875). As in all other amphistomes obtained from the intestines of elephants and cattle, the worms, when fresh, were of a bright brick-red color. By the natives of India these parasites are called Masuri; but no description of the worms had been published prior to the account which I gave of the contributions forwarded by Major-General Hawkes, Mr Collins, and Mr Stanley.

I shall have occasion to speak of the elephant’s Masuri further on; but in the meantime I must remark that the generally received notion as to the parasitic cause of the earth-eating propensities of various animals seems to have some foundation in fact. Not alone from Major-General Hawkes in Madras, from Mr Folkard in Ceylon, and from various other trustworthy sources, have I been informed of this habit on the part of Indian horses, but Dr Rowe told me that Australian horses, and even sheep, infested with stomach-worms, are in the constant habit of consuming large quantities of sand. From all the facts that have come before me, I am inclined to think that gastric or intestinal irritation, however brought about, may induce the habit in question, parasites being only one of the many sources of irritation giving rise to symptoms of colic in solipeds and pachyderms alike. At all events the African elephants at the London Zoological Society’s Menagerie, as repeatedly witnessed by myself, are in the habit of swallowing large quantities of soft mud during the summer months, but no traces of masuri have as yet been detected in their fæces.

When by letter I informed Major-General Hawkes of an interesting find by Mr Collins of about a thousand Amphistomes in the colon of a horse that had died at Simla, the announcement called forth a reply which is sufficiently instructive to be quoted. Writing from Secunderabad in July, 1875, he says, respecting this “find:”--“Your statement has incidentally thrown light upon a subject which has puzzled many of us in this country. It occasionally happens that a horse, on being opened after death, is found to have accumulated in his intestines large quantities of sand and gravel. In a recent case this accumulation amounted to 14-1/2 lbs. Until recently it was always held that this gravel or sand could only be introduced with the animal’s food. All grain in this country is trodden out by bullocks on an earthen floor, and the grain undoubtedly contains a proportion of sand and gravel derived from this source. Although this ought to be carefully washed out before it is given to the horse, still, owing to the carelessness of the native horse-keepers, this cleaning is, I expect, often omitted. In the daily ‘feed’ of eight or ten pounds of grain given to each horse the utmost quantity of sand or gravel that could be found admixed therewith would not probably exceed two or three ounces; consequently it would take from 77 to 116 days to accumulate so large a quantity as 14-1/2 lbs. Now, the advocates of the theory of the gradual accumulation of sand in this way have never been able to explain why the grain, grass, hay, and other ingesta should pass in the ordinary way through the intestines, whilst this sand or gravel remains behind. One can understand the possibility of such substances as wool, hair, or similar matters concreting in the alimentary canal, though I believe they are usually found in the stomach, and not in the intestines; but how a most incohesive substance like sand can possibly accumulate in the gradual way required by their theory I have never heard even plausibly explained. On the other hand, the fact that horses are often excessively addicted to eating earth is well known; and if my memory serves me correctly, it was found necessary, about twenty years ago, to remove the mud-walls of the pickets surrounding some of the horses of a mounted corps in this presidency in consequence of this habit. Now, given the fact that the amphistoma has been found in the horse (as your specimens prove), may we not fairly suppose it possible that the animal resorts to the same mode of ridding himself of this parasite as does the elephant? and also, would it not in a much more natural manner account for the large quantity of gravel or sand found in the intestines than does the theory of gradual accumulation? Reasoning from analogy, as in the case of the elephant, this eating of earth in the horse would be an instinctive effort on the part of the “host” to rid himself of the parasite. This self-taken remedy is doubtless in many cases quite effectual, though unnoticed. The fatal cases are probably those in which the horse has either overdone the remedy or where the system was too debilitated to carry off a quantity of sand or gravel that would otherwise have safely passed through the intestines of a horse in more robust health. The actual fact must, of course, be verified by careful investigation.”

Closely allied to the Masuri is an amphistome which I originally named Gastrodiscus Sonsinoii, but which should be altered as opposite (Fig. 62). It exceeds 1/2″ in length and 1/3″ in breadth (16 mm. long by 10 broad). Its discovery by Dr Sonsino was one of the results of his examination of sixteen carcases of solipeds that died during the Egyptian plague of 1876. Specimens having been forwarded to Panceri, Von Siebold, Leuckart, and myself, most of us at once agreed that the worm was new to science. Pointing to the genera, Notocotylus and Aspidocotylus, I explained its close affinity to the latter more particularly. Whilst Notocotylus has fifty supplementary suckers on its back, Aspidocotylus has nearly two hundred small ventral suckers seated on a convex disk. In Gastrodiscus a still larger number of suckerlets are placed in the deep concavity of a large gastric disk formed by the outstretched and inrolled margins of the body of the parasite. Zoologically speaking, the odd thing about this singular worm lies in the circumstance that its nearest fluke-relation, so to speak (Aspidocotylus mutablis), dwells in a spiny-finned fish (Cataphractus); and this fish itself forms an aberrant genus of the family to which it belongs (Triglidæ). From what has been said it will be seen that our Gastrodiscus must not be confounded with Cotylegaster cochleariform (or with its synonym Aspidogaster cochleariformis), to which parasite Von Siebold was, I believe, induced to refer it. Like most of the true amphistomes, the worm in question infests the intestines. Although discovered by Sonsino at Zagazig in plague-affected corpses, there is no reason to suppose that this helminth was in any way etiologically connected with the Egyptian epizoöty.

The tapeworms of the horse are of great interest practically. Excluding Sander’s Tænia zebræ, which was doubtless T. plicata, at least five species have been described, but they may probably be all reduced to two distinct forms and their varieties. Whilst Tænia plicata acquires a length of three feet, the strobile of T. perfoliata never exceeds five inches. The lobes at the base of the head in the latter are distinctive. The former is usually confined to the small intestine, but the perfoliate worm often occupies the cæcum and colon in great numbers. As regards T. mamillana, I may say that neither Gurlt’s descriptions nor his figures are convincing. The worm is, I believe, identical with T. perfoliata. In like manner, after going into the matter with some care, I am accustomed to speak of Mégnin’s T. inerme as T. perfoliata, var. Mégnini, and of Baillet’s T. innomé as T. perfoliata, var. Bailletii. I have examined great numbers of equine tapeworms, but whether my determinations on this point are correct or not, the case recorded by Mégnin is of remarkable interest. Clinically, indeed, it is not entirely unique, since a somewhat similar case has been recorded by Mr Poulton. In Mégnin’s equine patient the autopsy revealed the presence of 200 bots, 153 lumbricoids, upwards of 400 oxyurides, and several thousand palisade worms, besides numerous tapeworms. In Mr Poulton’s patient large quantities of tapeworms were found in the duodenum (and in large sacs of the walls of other sections of the small intestine), and also myriads of the little four-spined strongyle, in addition to about a score of palisade worms. Both Mégnin’s and Poulton’s patients died suddenly; but the great interest attaching to Mégnin’s case arises from the boldness of manner in which the French savant interprets the phenomena of the intestinal sacculation in relation to the development of the tapeworms. M. Mégnin assumes that the sacs are due to the formation of polycephalous or cœnuroid scolices. Without contradicting Mégnin’s ingenious interpretation of the phenomena in question, I may say that the difficulty I have in accepting his view arises from the circumstance of the rarity of the occurrence of these sacs. In Poulton’s case of Tænia perfoliata, the sacs were present, and they were productive of similar results; but in the scores of other recorded cases of sudden death from the same species of tapeworm (as published by Mr Rees Lloyd, and myself), the presence of such sac-formations is not once mentioned. To be sure, their presence may have been overlooked, but this is scarcely likely, seeing the great care taken by Mr Lloyd in conducting the autopsies. I cannot dwell upon the subject at greater length. The presence of so many sexually-immature strobiles, combined with the existence of the intestinal wall sacs, certainly does seem to point to the existence of cœnuroid bladder-worms, but until the existence of the polycephalous scolex be actually demonstrated one must be cautious in concluding “that the horse nourishes at the same time the strobila and scolex of the unarmed tapeworm.” Practically, we now know for certain that not only are tapeworms capable of producing a fatal issue in isolated cases, such as those recorded by Mégnin and Poulton, but that they may also be productive of disastrous epizoöty, as proved by Mr Lloyd in the case of Welsh mountain ponies.

In this connection I may perhaps be pardoned for saying that this discovery in 1875 was one of the practical results directly issuing from the publication of my ‘Manual’ in 1874. The attention of the veterinary profession having been called to the subject of parasitic epizoöty, Mr Lloyd was the first to make search for helminths amongst some few of the carcases of the hundred and more equine animals that perished in South Wales. Two totally distinct epizoötics prevailed. In the Beacons district tapeworms alone were the cause of death, whilst in the Deangunid district scores of animals perished from strongyles. In another district a hundred animals perished from tapeworms. These parasites I identified as examples of Strongylus tetracanthus and Tænia perfoliata. Taking all the helminthological facts together we have made a great advance both in hippopathology and equine epidemiology; and, as I observed at the time, the scepticism which not unnaturally still exists (in reference to entozoa as a frequent cause of death amongst animals, both wild and domesticated) will sooner or later be dispersed by that wider attention to the subject which our labors have invoked.

In relation to equine disease the facts brought forward are too important to be dismissed in a single paragraph. As two distinct kinds of parasitic epizoöty were discovered, the circumstances connected with their separate detection must be noticed at greater length. Further on, I shall again deal with the helminthiasis due to strongyles. It was on the 17th of April, 1874, that I received from Mr Lloyd, of Dowlais, Glamorganshire, a communication calling my attention to a fatal epizoötic affecting ponies. He supposed the outbreak to be due to parasites. On the following day I also received a parcel containing portions of the lower intestines, which had been removed from one of the diseased animals. The victim in question, a pony mare, had died on or about the 12th of April, at Llangunider, Breconshire. Mr Lloyd states in his letter that he “presumes” that the pony’s death was caused “by the presence of small worms,” examples of which he now forwarded for the purposes of identification and investigation. He also sent some equine tapeworms. Mr Lloyd had already inferred that his small worms were “strongyles;” and in regard to the tapeworms he says:--“This species of parasite has caused, or is supposed to have caused, the death of at least one hundred mountain ponies.” The investigation being immediately proceeded with, I may so far anticipate my record of the results obtained as to state at once that the facts observed by me confirmed Mr Lloyd’s suspicions--proving, beyond a doubt, that the pony above mentioned had succumbed to injuries inflicted by myriads of minute strongyles. Not only did I find the fæcal matter of the colon loaded with mature strongyles, but the walls of the intestine were also occupied with encysted and immature forms of the same nematode species. To such an extent had infection taken place, that I was enabled to count no less than thirty-nine strongyles within the space of the one fourth of a square inch. All parts of the sections of the colon under examination were almost equally invaded; so that, taking the average, I am clearly within the mark in saying that every square inch of the gut yielded at least one hundred parasites. The walls of the entire colon must therefore have been occupied by tens of thousands of these creatures, to say nothing of the scarcely less numerous examples lying free or lodged within the fæcal contents of the bowel.

In a second and more extended communication, sent in reply to inquiries as to the cestodes, Mr Lloyd (whose letter I have abridged) writes:--“I regret that I cannot give you very full particulars respecting the tapeworms. During the last twelve months mountain ponies grazing on the lower districts of Breconshire, which comprise some of the highest mountains in South Wales, have been dying in great numbers, from what the farmers indefinitely term inflammation. From what I have seen and heard, it appears that there are three causes of death, the tapeworm, the small worms (which I presumed were a kind of strongyle), and catarrhal disorders, such as have been common among horses of late. By far the greater number of deaths (from what I can glean) have been caused by the parasites. In the Ystradfellte or Penderin districts there has been no investigation, although the disease has reigned there for a longer period, about eighteen months, with (from what I have heard) a larger number of deaths than elsewhere; so I shall let these remain for the present, as I have not had an opportunity to see or hear anything authentic about them. In the Talybont district the cause appears to be the small worms (like those I sent). The owner of the animals said that a month ago, when he went to look after his ponies, they were appearing quite well, and looked as well as he could expect them at this season, but he was astonished to find some of them a fortnight ago looking very lean and wasting, and he thought that the weather was the cause of it, yet resolved to see them oftener; the next time he saw them one was dead, and knowing of the loss in the neighbourhood, and fearing he would be a sufferer, he sought aid, applying to me. When I arrived two days following two more were dead, and they presented an emaciated appearance. The post-mortem examination revealed a healthy condition of the whole of the intestines, save slight thickening of some parts of the colon and rectum, which contained, enclosed in the mucous membrane, in cysts or minute sacs, worms coiled upon themselves. Each cyst, containing one worm, was best seen by transmitted light. The colon was nearly full of fæcal matter, which contained thousands of parasites scarcely visible. The largest were very few in number, not exceeding an inch in length and barely one sixteenth in diameter at the middle portion. They somewhat tapered at both ends. The cæcum was half full of fluid fæces, containing no visible worms; the rectum, with fæces of natural consistence, the examination of which revealed only two or three evident worms; so that the examination of fæces of living animals giving results like this would not assist the diagnosis, unless suspected. Small intestines--these latter contained about a dozen bots, which were nearly free, but had pierced to the muscular coat. I should think they had participated in the disease. The right lung had been slightly congested; nothing else abnormal to be seen. Possibly congestion of lungs would arise from the distress when pained with worms, for the pony was found on its back with its head in a thicket--it had not appeared to have struggled--with its teeth firmly closed.

“Respecting the animals affected with Tænia, it is remarkable that, as a rule, they are in fair condition. The average time they appear to be troubled with the worms is two months, and the symptoms observed have been many. They are at first seen to be unable to keep up with the other ponies, extending the head and turning the upper lip up, rubbing the quarters, staring coat, suddenly appearing distracted, seizing turf in mouthfuls when being griped or pained, others running away as fast as they can go, or rolling and kicking on the ground for five or ten minutes, then walking away as if nothing had happened, if coming down a slope quickly almost sure to fall headlong, easier caught, not unfrequently coughing, groaning noise, appetite good, and, what is peculiar in some of them, lameness of one of the hind limbs, mostly the near hind leg, with slight knuckling over at fetlock.

“Post-mortem appearance.--Abdominal viscera normal, save rectum, which is in some places slightly congested; colon nearly full of fæces, no worms; cæcum, in which worms are alone found, is nearly full of fæcal matter of thicker consistence than usual, and nearly half made up of worms; stomach half full of partly digested food; heart and lungs healthy; Schneiderian membrane injected; mucous membrane of trachea and part of larger bronchiæ of a more or less livid colour (which may be owing to asphyxia); corner of tongue bitten off; mouth very close.

“Several animals were found at times lying dead together.

“Of the Tænia as many as three or four ponies, which some hours previous had been seen grazing unaffected, were found dead on the same spot; and this to my own knowledge, one farmer having lost ten.

“Of the small worms I have been told by a farmer that in his district one of his neighbours had lost twelve ponies.”

As I had partly misunderstood my informant’s original statement, Mr Lloyd, in a third communication, repeated the evidence, emphatically reminding me that “the ponies affected with tapeworms are in a district six or seven miles distant from those affected with strongyles. Those troubled with tapeworms are in good condition, as a rule, up to death; they are noticed to be troubled generally for two months previous to death, and may be seen at one hour grazing and apparently well, and dead or dying the next hour. As many as four have been found dead at the same spot. In this (the Beacons) district the tapeworms alone have been found and not a single strongyle. In the Deangunid district strongyles only have been found, such as I sent you. The ponies have been noticed ailing for three or four weeks, becoming rapidly emaciated and dying from exhaustion. In tapeworm-affected animals the cæcum is nearly half full of these parasites. The animals thus affected are on the red sandstone formation, whilst those affected with strongyles occur on the limestone formation--the latter affording the drier situation.”

Being on the teaching staff of the Royal Veterinary College I was particularly glad to have the authority of an experienced veterinary practitioner to testify to the injuriousness of Tænia perfoliata in the horse. Over and over again I had pointed out to the members of my class the desirability of examining the fæces of solipeds where obscure symptoms of intestinal irritation existed. Not only so; at the request of friends I wrote out prescriptions suitable for equine patients suffering from tapeworm. I felt the more indebted to Mr Lloyd, inasmuch as his practical views served to strengthen the propositions I had advanced in connection with internal parasites as a frequent cause of epizoötics. My views were criticised at the time with a vigour and warmth well worthy of those who are afraid of advancing epidemiological science too rapidly; but it seems that so far from my having overstepped the bounds of moderation in this matter I had, in reality, been too cautious. Certainly it can now no longer be said that “the symptoms created by tapeworms in the horse are of little or no consequence.” Here, therefore, I repeat, we have made a clear and rapid advance in our knowledge of helminthic disease; and from the impulse thus given to hippopathology it is only reasonable to look for still further advances in veterinary medicine. By-and-by, the scepticism which not unnaturally exists in reference to entozoa as a frequent cause of death amongst animals, will be dispersed by even yet clearer enunciations regarding the important part these parasites play in the destruction of our most valuable creatures.

Apart from the question incidentally raised by Mégnin as to their origin and mode of development, the presence of larval cestodes in horses cannot be passed over. The common hydatid (Echinococcus veterinorum), though not of frequent occurrence, is occasionally productive of fatal consequences. Very interesting cases are recorded by Messrs Henderson and Kirkman, aided by the valuable comments of Professor Varnell. Mr Hutchinson observed an hydatid in a horse’s eye, and Mr Vincent noticed lameness, as resulting from hydatids. But one of the most interesting cases of hydatids in solipeds is that described by Professor Huxley, from a zebra that died at the Zoological Gardens in 1852. As stated in Huxley’s elaborate memoir (freely quoted in the first part of this work), the liver was found to be “one mass of cysts, varying in size from a child’s head downwards.” The zebra’s death was purely accidental, as it broke its neck while at play in the paddock. The long bladder-worm of the horse (Cysticercus fistularia) is entirely unknown to me, and, as before suggested, may be a mere variety of the C. tenuicollis of ruminants. An authentic instance of the occurrence of the gid hydatid (Cœnurus cerebralis) in the horse is recorded by Gurlt. Lastly, in relation to the question of food, it is worthy of remark that whilst beef, veal, pork, and even mutton, are apt to be measled, the muscle-flesh of horses is not liable to be infested by Cysticerci. This is a fact in favor of hippophagy.

The nematodes of solipeds are very numerous, and first in importance must be placed the palisade worm (Strongylus armatus). This worm was known to Ruysch (1721). The old naturalists recognised two varieties (major and minor). These we now know to be merely the final stages of growth of one and the same entozoon; and in both stages the worm inflicts severe injury upon the bearer, chiefly, however, whilst wandering through the tissues. The palisade worm has acquired notoriety principally on account of its causing verminous aneurism, nevertheless, this pathological change is not, in itself, the most disastrous evil produced by the worm. In the adult state the female reaches a length of two inches, whilst the male rarely exceeds an inch and a half. The posterior ray of the caudal membrane or hood of the male is three-cleft. In both sexes the head is armed with numerous, closely-set, upright denticles, presenting the appearance of the teeth of a circular saw or trephine. The eggs are elliptical and somewhat constricted at the centre, their contents forming embryos after expulsion from both parent-worm and host. The larvæ are rhabditiform, changing their skin, in moist earth, in about three weeks, at which time they part with their long tails. According to Leuckart, they pass into the body of an intermediate bearer before entering the stomach of the definitive or equine host. From the alimentary canal they pass to the blood-vessels, causing aneurism, and thence they seek to regain the intestinal canal, where they arrive at sexual maturity. It is during their migratory efforts that they give rise to dangerous symptoms in the bearer, not unfrequently causing the death of young animals, especially yearlings. In the adult state the worm is also dangerous to the bearer, as it produces severe wounds by anchoring to the mucous membrane of the gut.

The proofs we possess as to the frequency of abdominal, especially mesenteric, aneurism from this source are overwhelming. Prof. Brüchmüller estimated the percentage of aneurismal horses, six years old and upwards, at 91 per cent., and it is a matter of common observation in veterinary dissecting rooms that verminous aneurism is rarely or never absent in the ass. Professors Dick, Simonds, Pritchard, Williams, and many other English and Scotch veterinarians of eminence, have all borne testimony of this kind, and, for myself, I may say that one of the earliest pathological appearances with which I became familiar, some thirty years back, was that presented by mesenteric arterial disease of the ass. In relation to fatal colics in the horse the study of verminous aneurism is of the highest moment. On this subject Prof. Friedberger has published some valuable lectures, in which, amongst other points, he incidentally remarks upon the comparative freedom of military horses from aneurism as compared with ordinary laboring horses. This arises partly from the fact that the latter are not cared for to the same extent, dietetically and otherwise; and, moreover, cavalry horses are, as a rule, younger than ordinary working animals. Whilst Friedberger, in his suggestive brochure, does ample justice to the writings of his colleague, Dr Bollinger, it may be said, in like manner, that he does not fail to recognise his great indebtedness to the researches of Leuckart. So practically important, however, do I deem Bollinger’s summary of the whole subject in relation to the hippopathological aspects of parasitism, that I feel it desirable to record his conclusions at full length. No professional man having any pretensions to a knowledge of the veterinary art--or, for that matter, to parasitism in relation to sanitation--should remain uninformed on this subject. Dr Bollinger’s results are thus stated:

1. The worm aneurism of the visceral arteries of the horse, existing in 90 to 94 per cent. of adult horses, has a general correspondence with the aneurisma verum mixtum of man. It is, however, distinguishable from the same by its seat, cause, character of its walls, contents, and mode of termination. The worm-aneurism arises from a parasitism of the palisade worm (Strongylus armatus), owing to an inflammatory affection of the arterial walls which it causes, and which one may describe as a recurrent traumatic endo-arteritis. This holds good for all the visceral arteries, with the exception of the abdominal aorta, in which an aneurism may arise from local increase of pressure.

2. The formation and further development of the aneurism is also favored by the narrowing of the arterial calibre, which is caused by the inflammatory swelling of its walls, and also by the contemporaneous formation of a thrombus (clot), this latter still further supporting and exciting the inflammation of the inner coat.

3. Whilst the causes above mentioned (and of these more particularly the continued presence of the palisade worms and the plugging of the smaller arteries by thrombi) favor the growth of the worm-aneurism, the small size of the same, notwithstanding the years it has existed, is explained by the considerable hypertrophy of the muscular layer, by the tough fibrous capsule formed in many cases by the connective tissue of the mesentery, and by the adhesion of the intestines to the perpendicular and free-lying anterior mesenteric artery; in particular this last-named circumstance does not allow of any very considerable shortening of the mesenteric artery, which would necessarily be accompanied by considerable dilatation of the arterial tube.

4. The favorite seat of the worm-aneurism is the trunk of the anterior mesenteric artery, directly at its origin from the abdominal aorta. Most frequently that part of the arterial trunk is dilated from which the arteria ilea, cæcales, and colica inferior (arteria ileo-cæco-colica) arise, less frequently the arteria colica superior at its origin, and the arteries of the cæcum and colon in their course in the meso-cæcum and meso-colon. The verminous aneurism also occurs in the cœliac artery (Bauchschlagader), in the posterior mesenteric artery (Gekrös-arterie), in the renal artery, and in the abdominal aorta. A horse is not unfrequently afflicted with several aneurisms of this kind at one and the same time. Thus in one case (described by Bollinger) there were six of these aneurisms affecting the abdominal aorta and its branches in the same horse. The verminous aneurism may occur from the sixth month of life onwards, and with increasing age; the number of horses free from such aneurisms becomes continually smaller.

5. The size of the aneurism varies between that of a pea and that of a man’s head. The dilatation is, as a rule, equal on all sides, the form being usually thumb-shaped or bottle-shaped, passing into that of a cone or long oval figure. This general configuration is principally due to the free and moveable situation of the anterior mesenteric artery.

6. In contrast to aneurisms in man, the walls of the worm-aneurism of the horse are almost without exception indurated. In addition to the mesenteric connective tissue, all the arterial coats, and especially the tunica media, generally take part in this induration. The hypertrophy of the media, which stands unique in respect of what is known of arterial disease, forms a compensatory action of the arterial wall, analogous to the muscular hypertrophy of the heart in valvular disease. This change in the media points to the fact that in the development of aneurism in man the early disturbance of the nutritive process in the tunica media is not a less essential factor than the degeneration of the tunica intima.

The changes in the intima are the least constant. They present all stages of progressive and retrogressive metamorphosis, from simple induration to ulceration and calcification. In the walls of the verminous aneurism one not unfrequently finds all the pathological changes exhibited by atheroma in man. Calcification is a common form of the retrograde process, and, in very rare cases, may pass on to the formation of true bone.

7. In addition to the palisade worms, one almost constantly finds a parietal thrombus contained in the aneurism. It covers the inner wall either partially or completely, being in the latter case perforated for arterial offshoots. This clot may occlude the artery, and it is not unfrequently continued into the arterial branches (peripherally) or into the aorta (centrally). Amongst the various changes that the clot undergoes, organisation of its outermost layer and softening are the most frequent. The constant occurrence of this clot is due to the presence of the worms, to the inflammation, ulcerative and regressive affection of the intima, and to the dilatation of the arterial tube.

8. The palisade worms are seldom absent from aneurisms of the horse. Their not being present is merely an accidental circumstance. On the average, nine palisade worms go to a verminous aneurism, and eleven in the horse. The highest number of worms found in one horse reached 121. Not unfrequently, also, palisade worms, or their coverings in the form of larval skins, are found in the aneurismal walls. The immigration and emigration of the palisade worms out of the intestine into the aneurism, and the reverse, take place probably, as a rule, within the arterial circulation. The path of the worm does not appear to be always the same, inasmuch as they can also wander through the peritoneal cavity. The worms found in the aneurismal walls are probably mostly only strayed specimens.

9. From a comparative pathologico-anatomical point of view, the developmental history of the aneurysma verminosum proves that a circumscribed endo-arteritis can determine the formation of an aneurism.

10. Like the worm-aneurism itself, atheroma of the abdominal arteries arises from a circumscribed acute and subacute endo-arteritis. The histological changes in the secondary atheroma of horses are perfectly analogous to those of the spontaneous atheroma of man. Idiopathic atheroma, as seen in man, does not occur any more in the horse than in the other domestic animals. Atheroma in the horse is always secondary. To be sure, one observes an idiopathic chronic endo-arteritis in many abdominal arteries of the horse, which, however, never exhibits indications of atheromatous degeneration.

11. In consequence of its position the worm-aneurism of horses is not open to physical examination, and on that account cannot be diagnosed by physical signs; moreover, it offers no characteristic symptoms. Its termination by rupture is extremely rare, the aneurisms of the abdominal aorta being more disposed to rupture than those of the anterior mesenteric artery. Of eighteen cases of known perforation, fifteen opened into the peritoneal cavity, and three into the bowel. The dangerous symptoms of the worm-aneurism are exclusively due to embolism and thrombosis of the affected artery, arising from the parietal clot. The latter becomes especially dangerous through its increasing size and the softening which often accompanies it. The absorption and shrinking of this parietal clot, be it organised or not, is materially assisted by the high pressure to which it is exposed.

12. The very marked symptoms of vascular obstruction--the sero-hæmorrhagic intestinal infarct--in embolism and thrombosis of the mesenteric arteries are easily explained by paralysis of the muscular coat of the intestine, by the absence or paucity of valves in the portal vein, by the readiness with which meteorismus (or flatus) arises, especially in herbivora, and by the loose consistence of the intestinal walls or villi.

13. The occlusion of the intestinal arteries, especially that arising suddenly, always has for its result a partial or complete paralysis of the portion of bowel which they supply. The palsy of the intestine causes the forward movement of the intestinal contents to cease, a stoppage of the fæces, a hindrance to the discharge of fæces and gas, and also that exceedingly dangerous formation of gas (within the intestinal tract) which in the herbivora is so abnormal, both quantitatively and qualitatively.

14. In embolism and thrombosis of the mesenteric arteries the symptoms during life are entirely identical with those observed in the so-called colic of horses, as has been determined by numerous observations. The partial paralysis of the bowel, which is brought on by the embolism and thrombosis of the mesenteric arteries, forms in great part the chief and leading feature of the series of symptoms known as the “colic” of horses. The palsy of the bowel which arises in this way may explain also the frequent ruptures of the digestive canal and the greater number of its changes in position. The latter are specially favored by the structure of the abdominal viscera in the horse.

15. The old changes which one finds in the peripheral branches of the anterior mesenteric artery, in the form of expired and partly absorbed embolic and thrombolic processes (pigmentation, arterial and venous thrombi), particularly in connection with those arteries which are seats of the aneurism, decisively prove that the large majority of colics resulting in recovery, so far as they do not depend upon known injuries, are caused by paralysis of the bowel from embolism and thrombosis. The sudden occurrence, course, and result of these kinds of colics also testify to their embolic origin.

16. The œdematous, inflammatory, and hæmorrhagic processes that one often finds described as the cause of death in colic, almost exclusively depend on thrombosis and embolism of the mesenteric arteries, the cases forming about 40 to 50 per cent. of all fatal colics.

17. The rapid course in fatal colics, as well as the preponderating symptoms of dyspnœa in cases of recovery, is finally due to the abnormal development of gas in the alimentary canal. In addition to the diminution of the respiratory surface by the lofty position of the diaphragm, a direct gas-poisoning (carbonic acid and sulphuretted hydrogen) probably contributes to the intensity of the symptoms and the rapid course by diffusion of the abnormally developed gas out of the intestinal canal into the blood.

18. The variety of the anatomical derangements caused by embolism and thrombosis of the intestinal arteries is faithfully mirrored by the variety of the clinical symptoms and the different degrees in the intensity and course of the colic.

19. Amongst every 100 horses afflicted with internal disease, 40 are ill with colic. Among any hundred deceased horses 40 have perished from colic, and among 100 colic patients 87 recover and 13 die. The figures prove that neither amongst the epizoötic nor sporadic diseases of horses is there any other affection which occurs so frequently, or claims anything like so many victims. Like the frequency of the worm-aneurism, the amount of disease and mortality increases with advancing age. The etiology of the colic of horses finds in the thrombosis and embolism of the mesenteric arteries, with the consequent paralysis of the bowel, an all-sufficient explanation, whilst the causes of colic hitherto accepted were for the most part insufficient.

20. In a great number of cases the thrombus of the worm-aneurism is continued past the mouth of the anterior mesenteric artery, into the lumen of the aorta, and, as such, is the exclusive cause of the embolisms of the pelvic and crural arteries which bring about the intermittent hobblings (the author says “intermitterenden Hinken,” not “Hahnentritten,” the usual equivalent term for stringhalt). Considering the excessive frequency of the thrombus being continued into the aorta, it becomes highly probable that a great part of the diseases and lameness of the posterior extremities (“Hüft und Kreuzlähme, unsichtbarer Spath, &c.,” which may be rendered “sciatic and hip or spinal lameness, obscure spavin, &c.”) are due to occlusion of the arteries.

21. Owing to the fibrous thickening of the connective tissue of the root of the anterior mesenteric round the aneurism, and to the considerable size of the latter, disturbances of the innervation of the intestine, (as well as) hindrances to the passage of the chyle, and irregularities in the portal circulation may be created, which may well lie at the root of many chronic disturbances of digestion in horses.

22. Considering the great losses and heavy social disadvantages that are occasioned by the colic of horses to the horse-breeder, to agriculture, and to the general welfare, it is of the highest importance to discover means which should prevent the introduction of the embryos with the food, and, as a consequence, the migration of the palisade worms into the mesenteric arteries of the horse.

I wish it to be distinctly understood that the above summary is translated from Bollinger (Die Kolik; s. 257). Instructive cases have been recorded both at home and abroad. Prof. Varnell has remarked that “foals and yearlings suffer more from parasites in the paddocks than they do on adjoining farms where only a few animals are bred.” This is explained by the relatively greater amount of egg-dispersion proceeding from the infected brood-mares. It is quite evident that the lives of many valuable animals are annually sacrificed by the neglect of hygienic arrangements. The palisade worm is chiefly destructive to young animals, and as Mr. Percivall has well remarked, these parasites are “commonly the cause of lingering and hidden disease, terminating in death,” without any suspicion on the part of the practitioner as to the nature of the malady. Instructive cases of this form of helminthiasis are given by Messrs Littler, Wyer, Harris, Meyrick, Litt, Percivall, Tindal, Walters, Brett, Aitken, Mead, Clancy, Baird, Mercer, Wright, Seaman, Hepburn, and others.

Second only in clinical importance is the little four-spined strongyle (S. tetracanthus). The sexes, often seen united, are nearly of equal size, the largest females reaching nearly 3/4″. They infest the cæcum and colon, and have been found in all varieties of the horse, ass, and mule. The worm occurs in immense numbers and is a true blood-sucker. Its presence occasions severe colic and other violent symptoms, often proving fatal to the bearer. As already announced, in connection with my account of the tapeworms of the horse, this little worm may produce a virulent epidemic (epizoöty). In the sexually-immature state the worm occupies the walls of the large intestine, where it gives rise to congestion, ecchymosis, inflammation, and the formation of pus deposits. The species is readily recognised by its bright red color, by the four conical spines surrounding the mouth, by the two neck-bristles, and by the long three-lobed hood of the male, the posterior three-cleft ray having a rudimentary or fourth branch attached to its outer edge. In some specimens sent to me by Mr Whitney, I found this supplementary process fully twice as long as Schneider has represented it.

From the earliest times this entozoon has been confounded with the palisade worm. Rudolphi and several of his successors, and also in recent times Ercolani and Colin, regarded this worm as the progeny of Strongylus armatus. During my earlier examinations I likewise fell into the error of describing the immature worm as representing a new species. The parasites described by me as Trichonemes (T. arcuata) were identical with those which Prof. Dick had previously described as “worms at different stages of growth,” in his MS. sent to Dr Knox, 1836. Parasites of this kind were described by Dr Knox as “Animals similar to Trichina;” by Diesing as the “Nematoideum equi caballi;” by Mr. Littler as “Extremely small ascarides,” in a letter to Mr Varnell; by Mr Varnell himself as “Entozoa in various stages of growth;” and by Prof. Williams as “Entozoa from the intestinal walls,” in a letter to myself, dated March 13th, 1873. In reference, however, to Mr Varnell’s account of Mr Littler’s specimens I may observe that the appearances which he at first merely described as “blood spots,” he afterwards characterised as dark points “containing young worms in various stages of growth.”

As regards the course of development of this worm we have yet much to learn. Although the worm is a frequent cause of epizoöty in this country it appears to be but little known on the Continent. Krabbe makes no mention of the helminthiasis set up by the four-spined strongyle, but he points out that the young occupy the mucous membrane, in which situation they lie coiled so as to present to the naked eye the appearance of little dark spots (Husdyrenes Indvoldsorme, 1872, p. 17, ‘Aftryk. of Tidsskr. for Vet.’). However, Leuckart’s account of the appearances presented in a case brought under his notice is instructive. He writes:--“I have hitherto had only a single opportunity of examining the strongyle capsules in the intestinal membrane of the horse. Their presence is limited to the cæcum and colon, but they are so abundant in this situation that their numbers may be estimated by many hundreds. It was thus likewise in the case in question, the investigation of which by myself was rendered possible through the friendliness of Prof. Haubner of Dresden. The capsules were of oval form, and glimmered through the mucous membrane as opaque spots, mostly from one to three millimètres in size. In several of these capsules nothing was found beyond a greasy mass of a brownish color, which might readily be taken for a tuberculous substance; but the greater number of them contained a coiled worm, from three to six millimètres long, their breadth being 0·15 to 0·26 mm. (which is 1/166″ to 1/99″). They exhibited a highly colored stout intestine, and a thick-walled oral capsule of 0·022 mm. in depth and 0·025 mm. in breadth. On the dorsal side two three-cornered chitinous lamellæ arise from the shallow floor of the small oral capsule. The cuticle, notwithstanding its firm structure, was still destitute of annulations. The tail (0·15 to 0·18 mm. in length) was strongly marked off from the rest of the body, being of a slender cylindrical form with a rounded-off extremity. The development of the sexual apparatus had not yet commenced. Notwithstanding the great differences of size presented by the body, the structure of all examples was exactly the same to the minutest particular, without exception. Also the smallest specimens, which scarcely measured one millimètre, found in capsules of 0·3 mm. in diameter, were distinguishable only by the absence of the oral cup, whose position was represented by a slender and thickened chitinous cylinder, as obtains in the earliest parasitic juvenile condition of Dochmius trigonocephalus. The transformation to the form presenting an oral cup occurs through a moulting, which is accomplished already in examples of 1·5 mm. in diameter. Later, also, the worms cast their skins in their capsules, without, however, changing the oral cup. In regard to the final purpose of this metamorphosis, my investigations have left me entirely in the lurch; nevertheless, I do not entertain the smallest doubt that the worms which I have here described are the larval forms of Strongylus tetracanthus.”

From numerous examinations I have satisfied myself that the worms after escaping the walls of the intestine--and they may often be observed in the very act of passing--re-enter the lumen of the bowel to undergo another change of skin prior to acquiring the adult state. This they accomplish by rolling themselves within the fæcal matter of the horse’s intestine. The best examples I have seen of this phenomenon occurred in a case for the clinical particulars of which I am indebted to Mr Cawthron. Most interesting was it to notice these immature worms, each coiled within a sort of cocoon, which Mr Cawthron termed a cyst. All the forty little cocoons more or less resembled pills, the bright red color of their contained worms strongly contrasting with the dark color of the cocoons. They consisted of compressed débris, which under the microscope showed many common forms of vegetable hairs and parenchyma, besides raphides and chlorophyll-granules. Internally, there was a cavity corresponding with the shape of the worm. In one instance I noticed that the worm had nearly completed its ecdysis, a portion of the old skin still remaining attached to the tail.

As already remarked, the evidence respecting the frequency and destructiveness of this little worm in England is now quite overwhelming. In a series of papers contributed to the ‘Veterinarian’ (too long for full quotation here), I have endeavoured to do justice to the “finds” and observations of those members of the veterinary profession who were good enough to supply me with valuable notes and communications. In particular must my indebtedness to Mr Rees Lloyd be acknowledged, for, as previously observed, he it was who first recognised the parasitic character of the Welsh epizoötic outbreaks. In the Deangunid and Talybont districts these strongyles proved terribly fatal to mountain ponies. It appears that the owners of the animals, as soon as they perceived anything amiss, at once disposed of them by sale, evidently anticipating fatal results sooner or later. The facts connected with some of the isolated cases brought under Mr Lloyd’s care are especially interesting, as showing the virulence of the symptoms set up. Thus on the 9th of Feb., 1875, some time after I had identified the species from specimens he had sent me, Mr Lloyd writes as follows:--“The last case I had was one which had been sold in this way, and which had suffered now and then from colicky pains for the space of about two months. The animal had been drenched with febrifuges and rubbed with stimulating liniments about the throat. However, I was sent for one evening, about an hour before the patient’s death. I soon diagnosed the case as parasitic, and at the same time considered it to be a hopeless one. I remained with it the whole of the time, of which about forty-five minutes of the most acute pain was borne by the trembling beast, which was leaping, rolling, and tossing itself about with astonishing rapidity. The bulging eyes, gnashing teeth, foaming mouth, and sharp peculiar hoarseness, were pitiable to behold; when suddenly all was silent, he quietly rose to his feet, and nipped the grass as if nought had troubled him. I then trotted him quietly up a few yards of rising ground in the corner of the field, when he immediately got down to rise no more. The next day I examined him, and found myriads of the four-spined strongyles, a large number being encysted.” Mr Rees Lloyd’s account of this case is so graphic that I have reproduced it without abridgment. Speaking of another patient, a mare, he says, “she had voided thousands of these parasites, and was in a frightfully emaciated condition, but beyond a craving appetite there was little else to be noticed.” Notwithstanding the few diagnostic indications afforded, Mr Lloyd, being led by the history of the case to suspect worms, at once examined the fæces, when he discovered thousands of these minute nematodes. Clinically, these facts ought not to be lost sight of. In addition to Mr Lloyd’s cases I have received valuable particulars of others at the hands of Prof. Williams, Messrs Cawthron, A. Clarke, T. Gerrard, D. M. Storrar, and J. W. Whitney.

Practically, it is important to inform the persons most interested that an active “drench” may be serviceable in dislodging the free intestinal worms, but the administration of purgatives must not be persevered in. As in the somewhat parallel case of Trichinosis in the human subject, the fatality of the disorder depends not upon the free and mature worms, but upon the migrating and sexually-immature forms. All attempts by means of active drugs to poison the entozoa, when once they have gained access to the tissues (whether actually capsuled or not), are worse than useless. By all means let the animals have a dose of aloes in the first instance, followed by warm bran mashes; but thereafter let every care be taken to support the patient’s strength. Especially should the exhibition of turpentine be avoided. Without doubt the cause of this, as of other similar epidemics, is primarily referable to atmospheric conditions which favor the multiplication of parasites. As the practical man cannot alter these climatal changes, he must do his best to check the disorder by removing the victims to new localities; or, if the animals must remain in infected districts, by supplying them with various kinds of artificially prepared fodder, supplemented by carefully filtered water. In this way, I believe, epidemics may be arrested, but they cannot be stamped out altogether, except by the adoption of measures which would be alike impracticable and unwarrantable.

Passing to the consideration of other intestinal nematodes, the next in importance is the large lumbricoid (Ascaris megalocephala) found in all solipeds, including the zebra. Whilst the male worms rarely exceed seven inches in length, the females sometimes reach seventeen inches. Science is indebted to Schneider for setting at rest all doubt as to the specific distinctness of this worm. The far larger number of caudal papillæ at once distinguishes it from the lumbricoid of man and the hog. The equine Ascaris may occur in any part of the alimentary canal, but the small gut forms its proper head-quarters. The entire course of development of this worm has not been traced; nevertheless, Heller found human lumbricoids measuring less than the eighth of an inch. It is not likely that any intermediate host is necessary for the growth of the larvæ, prior to their access to the definitive host. I have reared the larvæ in impure water and in moist horse-dung, up to the size of 1/30 of an inch. They were then furnished with a completely-formed digestive apparatus. Davaine kept the intra-chorional embryos alive in water for five or six years. His experiments on rats, dogs, and on a cow, led to no decisive results; but it is important to know that the eggs of lumbricoids effectually resist dryness. According to Davaine, however, embryonal development is thus arrested (except in Ascaris tetraptera of the mouse).

Seeing how readily the most ordinary attention to cleanliness must suffice to prevent lumbricoid helminthism, it is scandalous that so many severe cases of disease from this source should ever and anon turn up and be reported. In no properly conducted stable are these large entozoa ever to be seen in any considerable numbers; for so long as the water-supply is good and the fodder clean there is no possibility of infection. A fertile source of infection, however, results from allowing horses to drink at foul road-side ponds and from open waters in the vicinity of stables and paddocks where foals are reared. Into the clinical bearings of the subject I do not enter, but a host of interesting records of lumbricoid disease may be found in veterinary journals, both home and foreign. These have their counterpart in the very similar cases recorded in the medical journals, and quoted by me in the 34th bibliography of this work. From Sonsino’s report these worms do not appear very common in Egypt, but the veterinary inspector, Dr Zunhinett, had occasionally met with them. From Messrs W. Awde, J. B. Wolstenholme, and other English veterinary surgeons, I have received notes of interesting cases, but in this connection I can only further refer to the published cases of Messrs Anderson, Boddington, Cartwright, Harrison, Moir, and Wallis. The French cases, by M. Cambron and by M. Véret, are particularly instructive. Many of the cases give fatal results. In one fatal instance a pupil of mine counted over 1200 of these worms, and in a similar fatal case Mr Lewis reports that he found the small intestine literally crammed, some thousands of worms being huddled together in large masses.

The next nematode of general interest is the pinworm (Oxyuris curvula). Professional men often confound it with the palisade worm, and it has even been mistaken for the rat-tail maggot (Helophilus). The longest males measure 1-3/4″, and the females often beyond 4 inches. This worm infests the colon in great numbers, the species being easily recognised by its long subulate tail. Like its much smaller congener infesting man, this worm occasions severe local irritation, clusters of the eggs often accumulating to form yellow incrustations at the verge of the anus. Equine pinworms are vegetable feeders, and, like human Oxyurides, are conveyed to the bearer in a direct manner. No horse properly looked after can be infested by these worms. Local washings and stable cleanliness being secured by an attentive groom, the animals are safe. Prophylactic measures of this kind are all-powerful against infection. Notwithstanding the ease, however, with which the oxyuris disorder may both be prevented and cured, we find it prevails extensively everywhere, alike in mankind and in solipeds. Dr Sonsino found these parasites abundant in Egypt, some of the worms reaching a length of nearly five inches (120 mm.). Mr Emmerson has given an interesting account of the prejudicial effects of these entozoa in the horses of Singapore.

One of the most remarkable equine parasites is that which I am in the habit of calling the large-mouthed maw-worm (Spiroptera megastoma), in contra-distinction to the small-mouthed species (S. microstoma). In this country the worm has attracted little notice, but through the kindness of Mr Spooner Hart, of Calcutta, and of Mr Percivall, of the 11th Hussars, stationed at Umballa, I have had abundant opportunities of examining this entozoon and the singular pathological appearances which it occasions. This parasite was first described by Rudolphi, who says:--“Spiroptera capitis discreti ore magno nudo, cauda feminæ rectiuscula acuta, mavis simpliciter spirali, corpusculis rotundis ad basim penis styliformis.” The worm was afterwards observed by Schultze, Chabert, and frequently also by Andral, but the best accounts of it are those given by Gurlt, Valenciennes, and Dujardin. Schneider has likewise done much to set at rest disputed points. Respecting the Spiroptère du Cheval, Dujardin, writing in 1844, observes that “Rudolphi at first studied this helminth from examples found in great number by Reckleben, at Berlin, in tubercles of the stomach of two horses. Quite recently, M. Valenciennes, at Paris, has found it frequently in tumours, from twenty to forty millimètres in size, in the stomach of eleven horses out of twenty-five that he had subjected to this kind of research. These tumours, lodged between the mucous and muscular layers of the digestive canal, are perforated by several holes traversing the mucous membrane. They are divided internally by a number of folds into numerous intercommunicating cavities, and sometimes filled with solid mucus and very many spiropteras. It is from examples collected by M. Valenciennes that I have been able to study the parasite.”

As regards the description of the worm, it is almost needless to say that Dujardin’s account is minute and admirable in all respects. In fact, no naturalist ever exceeded the Rennes savant in carefulness and accuracy of detail. An interesting point connected with these stomach-worms lies in the circumstance that Gurlt recognised two varieties, one of which he termed Sp. meg., var. major. It remained for Schneider to show that the larger worms formed an altogether distinct species, which he termed Filaria microstoma (‘Monogr.,’ l. c., 1866, s. 98). It was not unnatural that Rudolphi and his successors should confound these two forms together, and it is also not a little curious that the smaller of the two species has the larger mouth. Practically, veterinarians will probably rest content to know that whilst the Spiroptera megastoma occupies tumours in the walls of the stomach, the S. microstoma is always to be found free in the cavity of that organ. Any helminthologist who may chance to have read the Ceylon Company’s report on the fatal epidemic affecting the mules of the Mauritius in 1876 can scarcely fail to have observed that the worm called Ascaris vermicularis by Mr Bradshaw is none other than our Sp. megastoma. The description of the tumours as “reticulated” sufficiently explains their honeycomb-like appearance, but I think that the expression “alveolar” would better convey their true pathological character. Mr Spooner Hart compared these structures, which he terms “abodes,” to mole-hills, but there is no good ground for supposing that the wanderings of the parasites are in any sense comparable to the burrowings of the mole. In like manner the expression “nidus,” employed by Mr Bradshaw, though suggestive of their nest-like appearance, is to some extent misleading, as it implies that the worms form a nide or brood. Possibly, it may turn out that all the nematodes in each tumour have been bred in the spot where they are found, but hitherto they have only been seen in the adult state. Earlier stages of growth should be diligently sought for. Widely dissimilar as the two maw-worms are, it would not greatly surprise me to learn that Sp. megastoma and S. microstoma are dimorphic conditions of one and the same entozoon. At all events, Ercolani’s determination of the relations subsisting between Ascaris inflexa and A. vesicularis suggests a possible analogy of this kind. I may mention that the male Spiroptera megastoma reaches nearly one third and the female one half of an inch in length. A constriction separates the head from the body. The mouth is surrounded by four thick horny lips, the dorso-ventral pair being the larger. The tail of the male is spirally twisted, and furnished with lateral bands supported by three or four ribs. It carries two curved spicules of unequal size. There are five pairs of caudal papillæ, the tail being bluntly pointed in both sexes. The vulva of the female is placed about 1/7″ below the head. The eggs are linear or very narrow, and furnished with thick shells. According to Sonsino, who found Sp. megastoma in five out of sixteen Egyptian horses, the verminiferous growths are usually seated near the pyloric end of the stomach, as many as four tumours occurring at one time. Neither Sonsino nor any other observers already quoted appear to think that these morbid changes in any way interfere with the healthy performance of the gastric functions. However, I am of opinion that at least one recorded fatal case of parasitism, producing rupture of the stomach, affords an instance, however rare, of the injurious action of this entozoon. It is reported under the signature of “Argus,” quoted below.

In this connection I may mention that in 1864 Prof. Axe observed some small worms, scarcely visible to the naked eye, in the mucous membrane of the stomach of a donkey, the same worms being subsequently observed in three other donkeys brought to the dissecting room of the Royal Veterinary College. From the examination of a drawing of one of the male worms, executed by Prof. Simonds, I am led to believe that the parasites are entirely new to science. The hood being well marked there can be no doubt as to the strongyloid affinities of the worm. I therefore propose to call the worm after its discoverer (Strongylus Axei).

In regard to Sp. microstoma, the males measure up to 2/3″, whilst the females have a long diameter of 3/4″ or rather more (10‴). The small-mouthed maw-worm lives free in the stomach, and, as Krabbe observes, not unfrequently in very considerable numbers. It does not appear to be capable of injuring the host.

One of the most interesting equine nematodes is the eye-worm. Most veterinary writers speak of it as the Filaria oculi, but to helminthologists it is better known by the more correct designation, F. papillosa. Though commonly obtained from the eyeball and its tunics, the worm infests various tissues and organs of the body, being found in the thorax, abdomen, membranes of the brain, muscles, and cellular tissues. It infests the ass and mule, and also horned ruminants. The males attain a length of three inches and the females seven inches. The head is broad, with a gaping mouth armed with a ring of chitine and two prominent denticles. There are also two papillæ on the neck near the middle line, besides sixteen caudal papillæ, eight on either side. The tail of the male is spirally twisted, that of the female only slightly curved. Notwithstanding the many opportunities afforded of examining this parasite in the fresh state, very little is known respecting its origin and course of development. Dr Manson, who found that the mouth was armed with a five- or six-toothed oral saw, considers that the eye is not a proper resting place for the parasite, and that when one wandering worm comes across the track of another it follows it up from sexual instinct, and thus several may be found together in one place. The tracks are readily seen by the naked eye. Dr Sonsino speaks of it as a “yellow line.” This Italian observer found the worm in twelve out of the sixteen solipeds he examined during the plague. Each horse showed from two to a dozen worms “in the peritoneal cavity, wandering free on the serous lining, without causing any apparent mischief to the membrane.” On one occasion Sonsino found the worm in the liver. From the similarity of habit there can be little doubt that the cases of guinea-worm (F. medinensis) recorded by Clarkson and others, as occurring in the horse, were merely examples of F. papillosa. I think so all the more because the lamented Fedschenko verbally expressed to me his astonishment that I had in my introductory treatise (p. 387) spoken of the Dracunculus as an equine parasite. I did so on the authority of others. To the Rev. Horace Waller I am indebted for specimens of the eye-worm brought from Assam, and to Mr Spooner Hart for others sent from India. For examples occurring in England I am indebted to Mr Haydon Leggett, who, in 1875, sent me three specimens extracted from the eye of a five-year-old mare. Mr Steel has also given me an example of F. papillosa taken from the peritoneum of a donkey. Similar cases are constantly occurring in the practice of veterinarians in Hindostan. Highly interesting Indian cases are recorded by Kennedy, Molyneux, Twining, and Breton, and in addition to these I may also particularise those of Macnamara, C. Percivall, Hickman, Clarkson, Skeavington, and Jeaffreson. The cases by Lee and Grellier also deserve attention.

Another species of thread-worm (Filaria lacrymalis) is occasionally found in the horse between the lids and eyeball. It is a comparatively small and harmless parasite, the males measuring 1/2″ in length and the females 2/3″. It also infests the ox. Both the large and small eye-worms are viviparous, and, not improbably, both of them are the means of conveying embryonic Filariæ into the circulation. Be this as it may, we owe to Dr Sonsino the discovery of hæmatozoa in an Egyptian horse. The larval worm was provisionally named by him Filaria sanguinis equi. The microscopic nematodes closely resemble the larvæ of F. sanguinis hominis, but they are smaller. The horse from whose blood Dr Sonsino obtained the minute worms was also found, by post-mortem examination, to have been infested by Filaria papillosa, a circumstance which naturally suggested a genetic relation between the larval and adult parasites. Similar, if not the same, microscopic worms had been previously discovered by Wedl, who primarily and independently regarded them as embryos of F. papillosa. Another curious filaria-like entozoon is the reticulated threadworm (Onchocerca reticulata). In England we have no acquaintance with this singular parasite, but it appears to be tolerably common in Italy. Excellent figures of it have been given by Diesing. Both males and females are in the habit of coiling themselves within the muscles, where they are found invested by a capsule of connective tissue. When unrolled the sexes are found of equal size, acquiring a length of 1-1/2″. The worm has a simple unarmed mouth, its body being marked by a series of annulations formed of incompletely anastomosing rings. It does not appear to possess any clinical importance.

In connection with the equine nematodes I need only mention the lung-worm (Strongylus micrurus). Its importance in relation to the production of husk or parasitic bronchitis in calves has already been considered. The worm is rarely productive of mischief amongst solipeds, nevertheless, in the dissecting-room subjects at the Royal Veterinary College, the presence of these parasites in the lungs is frequently noticed. Lastly, it only remains for me to observe that the renal strongyle (S. gigas) is occasionally seen in the horse. In 1792 M. Chabert found one in the left kidney, and similar cases have since either been witnessed or reported by Rudolphi and Leblanc.

Of the numerous insect parasites and tormentors of solipeds the gadflies (Œstridæ) demand chief attention. For special description of the forms, Brauer’s monograph is the most, and, in fact, the only reliable authority. Here it is not possible to give the characters of the various equine species, of which at least half a dozen are known to science. As remarked by me in the special chapter contributed to Prof. Williams’ well-known veterinary treatise, the common gad-fly (Gastrophilus equi) attacks the animal whilst grazing late in the summer, its object being, not to derive sustenance, but to deposit its eggs. This it accomplishes by means of a glutinous excretion, causing the ova to adhere to the hairs. The parts selected are chiefly those of the shoulder, base of the neck, and inner part of the fore legs, especially about the knees, for in these situations the horse will have no difficulty in reaching the ova with its tongue. When the animal licks those parts of the coat where the eggs have been placed, the moisture of the tongue, aided by warmth, hatches the ova, and in something less than three weeks from the time of the deposition of the eggs, the larvæ make their escape. As maggots they are next transferred to the mouth, and ultimately to the stomach along with food and drink. A great many larvæ perish during this passive mode of immigration, some being dropped from the mouth, and others being crushed in the fodder during mastication. It has been calculated that out of the many hundreds of eggs deposited on a single horse, scarcely one out of fifty of the larvæ arrive within the stomach. Notwithstanding this waste the interior of the stomach may become completely covered with “bots.” Whether there be few or many, they are anchored in this situation chiefly by means of two large cephalic hooks. After the bots have attained perfect growth they voluntarily loosen their hold, and allow themselves to be carried along the alimentary canal until they escape with the fæces. Many persons suppose that during their passage through the intestinal canal they re-attach themselves to the mucous membrane, thereby occasioning severe intestinal irritation. This is an error. In all cases they sooner or later fall to the ground, and when transferred to the soil they bury themselves beneath the surface, in order to undergo transformation into the pupa condition. Having remained in the earth for a period of six or seven weeks they finally emerge from their pupal-cocoons as perfect dipterous insects. It thus appears that bots ordinarily pass about eight months of their lifetime in the digestive organs of the horse.

That they are capable of giving rise to severe disease there can be no doubt, but it is not often that the disorder is correctly diagnosed, since it is only by the passage of the larvæ that the practitioner can be made aware of their presence. Mr J. S. Wood has published a case of tetanus in a mare, associated with the larvæ of Œstrus equi, and Mr J. T. Brewer has also given a case where the duodenum was perforated by bots. Mr Goodworth records an instance of pyloric obstruction from the same cause, and Mr W. Coupe informed me in 1876 that he had a drove of foreign ponies under his care, all of which suffered irritation from hæmorrhoidal bots. He removed them with a pair of forceps. Although frequently said to do so, the common bot does not attach itself to the rectum before finally escaping the host. The larvæ of G. hæmorrhoidalis normally reside there. In this situation they seriously inconvenience the bearer. The bots of G. nasalis are often confounded with those which ordinarily occupy the stomach of the bearer. The larvæ of G. nasalis commonly reside in the duodenum near the pylorus. According to Schwab and Brauer, they rarely occupy the stomach. As occurs in the common species, this bot passes away with the fæces, and does not attach itself to the lower bowel. The bots of Brauer’s G. inermis much resemble those of G. equi, but they are much smaller and attach themselves to the wall of the small intestine. The bots of G. pecorum, which dwell in the rectum, are readily recognised by their peculiar form and scanty spination. They are pointed in front and truncated posteriorly. An assinine variety of G. equi has been described by Bilharz, whilst another distinct species (G. flavipes) attacks the ass and mule. The bot-larvæ of the latter host require recognition and description. A great variety of other equine bot-flies have been described, but all, or nearly all, of them are mere synonyms of the above-mentioned forms. For the limitation of the species I accept Brauer’s authority, and likewise his nomenclature. A great deal of nonsense has been written respecting bots. It is a relief to believe that G. (Œstrus) veterinus, G. ferruginatus, G. jubarum, G. (Œ.) Clarkii, G. salutiferus, G. subjacens, and many others, are not good species, at least that they are mere synonyms. In regard to the occurrence of subcutaneous bot-like maggots in the horse and ass, no doubt need exist on this point. I am indebted to Mr Percy Gregory for characteristic specimens taken from the back, neck, and withers of a four-year-old gelding. They appear to correspond with the Hypoderma Loiseti of Joly. Similar maggots have been found in the ass by Herr Erber, but Brauer refers these to H. silenus. Prof. Brückmüller published a case where the brain was infested by larvæ; and Mr Shipley has sent me an example of H. equi, which he states he removed from the choroid plexus of the brain. In addition to the cases by Woods, Goodworth, and Brewer, already quoted, others have been published by Tyndal and Cartwright.

Amongst the numerous other parasitic dipterous larvæ one must notice the rat-tailed maggots (Helophilus). A genuine instance of this kind has been brought under my observation, but the example recorded by Professor Axe was spurious. Professor Simonds and myself saw this supposed maggot, which was merely a very stout and pregnant Oxyuris curvula. Another genuine case was published by Mr. Stanley. This is quoted by A. Numan in his essay on Cœnurus. I have previously mentioned my having received an Helophilus-larva that had passed from the human body. One of the most troublesome external parasites is the so-called horse-tick or forest-fly (Hippobosca equina). They attack the abdomen, flanks, and inner part of the thighs in great numbers, occasioning great distress to the bearer. Being of leathery toughness their bodies are not easily crushed, and they are removed only with great difficulty. There is an equine disease in Sweden called Stackra, which is erroneously attributed to injuries produced by a species of fly-maggot (Lixus) which lives on the fine-leaved water-drop wort (Phellandrium). As regards the so-called free parasites, or rather non-parasitic obnoxious insects, which torment solipeds, it is impossible even to enumerate them. The tsetse of South Africa (Glossina morsitans) is terribly fatal to the horse, but it is said that the mule, ass, and zebra do not suffer from its bites--an immunity shared by swine, goats, antelopes, and man himself. Major Vardon’s rash experiment (based on the supposition that horses deprived of fresh green food would not suffer from the attacks of the fly) proved fatal to an animal which he purposely exposed on a much infested hill-top. The horse died ten days after it was bitten. According to Chapman, the bites of four tsetse flies are sufficient to kill an ox, but in man the irritation produced is very slight. Amongst other insects proving troublesome to solipeds may be mentioned the leg-sticker (Stomoxys calcitrans), the clegg (Hæmatopota pluvialis) which is very abundant in the West Highlands, various species of Tabanidæ and Asilidæ (Tabanus autumnalis, T. bovinus, Chrysops cæcutiens, Asilus crabroniformis), and also a host of ordinary flies and gnats (Muscidæ and Tipulidæ), as, for example, Anthomyia meteorica and Culex equinus. In India the bite of a species of Simulia gives rise to the formation of open sores of the most intractable character. As regards hemipterous insects it may be said that many species of lice (Anoplura) produce what is called phthiriasis or lousiness in the horse, some of them being derived from poultry. The best known species are Trichodectes equi, T. scalaris, Hæmatopinus equi, H. vituli, H. eurysternus, and the ass-louse (H. asini). Of the half dozen or more species infesting the hen (belonging to the genera Goniocotes, Liotheum, &c.) it is not probable that more than one or, at most, two of them are concerned in the production of poultry-lousiness in the horse. As an equine disorder this kind of phthiriasis was first described by Bouley. Cases in England have been observed by Messrs. Henderson, Moore, and Woodger. For some account of cases of lousiness due to Hæmatopinus I am indebted to Mr S. Butters. As regards the scab, itch, and mange insects or mites (Acaridæ), three perfectly distinct forms are known. Adopting M. Mégnin’s classification they are Sarcoptes scabiei, var. equi, Psoroptes longirostris, var. equi (being the Dermatodectes equi of Gerlach), and Chorioptes spathiferus, var. equi, which is the Symbiotes equi of Gerlach. All the species have been beautifully illustrated by M. Mégnin, whose memoir has dispersed many of the clouds of error and misrepresentation which have hitherto surrounded the subject. Whilst Psoroptes forms the true horse-mite, and attacks various parts of the body, Chorioptes confines its attacks to the posterior regions. Messrs South and Day and myself have verified some of the facts recorded by Mégnin in respect of the structure and habits of this last species. Another kind of mite (Glyciphagus hippopodos) is stated to infest the ulcerated feet of horses. It would appear that no true ticks properly belong to solipeds; nevertheless, the common cattle-tick (Ixodes bovis) occasionally attacks horses. Probably several other species of Ixodidæ, known to infest other animals, behave in the same way. The Arachnidan called Pentastoma tænioides, though properly belonging to the dog, has on several occasions been detected in the nasal or frontal sinuses of the horse. Such instances are recorded by Chabert and Greve. The largest example of this singular entozoon seen by myself was obtained from the same situation, and presented to me by the late Mr C. B. Rose, whose writings I have frequently quoted in connection with the Cœnuri of rabbits.

BIBLIOGRAPHY (No. 50).--Aitken, J., “Worms in the Spermatic Artery of a Colt,” ‘Veterinarian,’ p. 683, 1855.--Anderson, J., “A Case of Strangulation of the Ileum (with Lumbrici),” ‘Veterinarian,’ p. 261, 1859.--(Anonymous), “Rupture of the Stomach, associated with the existence of Cysts between its Coats containing Worms,” ‘Veterinarian,’ March, 1864, p. 151.--(Anon.), “Extraction of Filaria oculi from the Horse,” by “Miles,” ‘Veterinarian,’ 1864, p. 218.--(Anon.), “Case of F. oculi in the Horse,” ‘Veterinarian,’ 1864, p. 218.--(Anon.), “Worms in the Coats of the Stomach of a Horse,” by “Argus,” in the ‘Veterinarian,’ 1865, p. 151.--Baird, W., “Notice of Sclerostoma in the Testicle of the Horse,” ‘Proc. Zool. Soc.,’ 1861.--Blanchard, “Anoplocephala perfoliata,” ‘Ann. des Sci. Nat.,’ 3rd ser., tom. x, p. 345.--Bollinger, O., ‘Die Kolik der Pferde und das Wurmaneurisma der Eingeweidearterien,’ Munchen, 1870. (Reviewed by myself in the ‘Veterinarian,’ Jan.-April, 1874.)--Bovett, “Existence of Filariæ in a Sinuous Ulcer of the Withers of a Mare,” ‘Veterinarian,’ p. 515, 1861.--Bradshaw, C., “Death of Mules from Parasitic Disease in the Mauritius (with remarks by Dr Cobbold),” ‘Veterinarian,’ Dec., 1876, p. 837.--Brauer, F., ‘Monographie der Œstriden,’ Wien, 1863.--Idem, “Œstr. (Hypoderma) Clarkii,” in ‘Verhandl. der zool.-bot. Gessellsch. in Wien,’ xxv, p. 75.--Idem, “On Cephenomyia trompe from the Reindeer,” ibid., p. 77.--Idem, “Hypoderma bonassi from the American Buffalo,” ibid. (all with figs.), 1875.--Breton, “On the Worm found in the Eye of the Horse,” ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. i, 1825, p. 337.--Brown, D. S., “The Œstrus equi, or Horse-bot,” the ‘Veterinary Journal,’ July, 1877, p. 14.--Brückmüller, “Larvæ in the Brain of a Foal,” from ‘Viert. für wissensch. Vet.,’ in ‘Veterinarian,’ p. 82, 1857.--Cartwright, W. A., “On Strangulation of the Bowels, associated with about 150 Bots, and also some 150 Ascarides, in the Horse,” ‘Veterinarian,’ p. 413, 1833.--Idem, “Case of about 200 ‘Bots in the Œsophagus’ of a Horse,” ibid., p. 400, 1828.--Chambron, “On a Parasitic Malady in the Horse,” from ‘Ann. de Méd. Vét.,’ in ‘Edin. Vet. Rev.,’ 1861; see also (Cambron) ‘Veterinarian,’ 1860, p. 612.--Clark, B., “Obs. on the genus Œstrus,” ‘Linn. Trans.,’ vol. iii, p. 289, 1797.--Idem, ‘An Essay on the Bots of Horses and other Animals,’ London, 1815.--Clarkson, N. F., “Case of Filaria oculi in the Horse,” ‘Vet. Rec.,’ vol. i, p. 73, 1845.--Idem, “Case of Filaria medinensis in the Horse,” ibid., 1845.--Cobbold, “On the Diptera (bots),” in a chap. on the Parasitic Diseases of Animals, in Williams’ work (l. c., Bibl. No. 48).--Idem, “Obs. on rare Parasites from the Horse,” ‘Veterinarian,’ Feb., 1874.--Idem, “Further remarks on rare Parasites from the Horse,” ibid., April, 1874.--Idem, “Fatal Epid. affecting Ponies,” ibid., June, 1874.--Idem, “Remarks on Mégnin’s Tapeworm,” ibid., Sept., 1874.--Idem, “Report on Parasites (sent from India by F. F. Collins and Spooner Hart),” ibid., Nov., 1874.--Idem, “Epizoöty in the Horse, more especially in relation to the Ravages produced by the Four-spined Strongyle (S. tetracanthus),” ibid., April, 1875.--Idem, “The Egyptian Horse Plague in relation to the question of Parasitism,” ibid., Nov., 1876.--Idem, “Description of the new Equine Fluke (Gastrodiscus Sonsinoii),” ibid., April, 1877.--Idem, “On Worm-like Organisms within the Mitral Valve of a Horse,” ibid., 1877.--Idem, “Entozoa of the Horse and Elephant” (see Bibl. No. 51).--Idem, “Observations respecting the Large-mouthed Maw-worm of the Horse,” ‘Veterinarian,’ Jan., 1877.--Couchman, T., “Worms in the Kidney of a Colt,” ‘Veterinarian,’ p. 145, 1857.--Coupe, W., “Fatal Parasitism in a Colt,” ‘Veterinarian,’ Dec., 1876, p. 844.--Davaine, “Les Cestoides,” in ‘Dict. Encycl. des Sci. Méd.,’ p. 591.--Dick (see Knox).--Dickens, C., “Joint-lameness in Colts, associated with and symptomatic of Lumbricoid Worms,” ‘Veterinarian,’ p. 601, 1863.--Dun, R., “Remarks on Entozoa of the Horse,” ‘Veterinarian,’ 1854, p. 445.--Dupuy (with M. Prince), “Filariæ in the Great Mesenteric of a Horse,” ‘Veterinarian,’ 1835, p. 570.--Emmerson, C., “Prevalence of Entozoa among Horses in the Island of Singapore,” ‘Veterinarian,’ 1861, p. 514.--Friedberger, F., ‘Die Kolik der Pferde,’ Berlin, 1874. (Reviewed by me in the ‘Veterinarian,’ Jan.-April, 1874.)--Fry, “Case of Worms in the Horse,” ‘The Hippiatrist,’ &c., vol. iii, p. 10, 1830.--Gamgee, J. (senior), “On Bots,” ‘Edin. Vet. Rev.,’ July, 1858.--Goodworth, S., “Obstruction of the Pyloric Orifice of the Stomach by Bots,” ‘Veterinarian,’ p. 410, 1837.--Grellier, J., “On the Worm in the Eye (of the Horse),” ‘Veterinarian,’ p. 18, 1844.--Harlan, R., “Case of a Colt killed by Worms,” in his ‘Med. and Phys. Researches,’ p. 554; see also ‘Med.-Chir. Rev.,’ 1836.--Harris, “A Case of Worms in the Arteries of a Colt,” ‘Veterinarian,’ p. 307, 1834.--Harrison, J. D., “The singular effect of Worms in the Stomach of a Mare,” ‘Veterinarian,’ p. 331, 1842.--Hickman, T., “Worm in the Eye of the Horse,” ‘Edin. Vet. Rev.,’ 1864, p. 653.--Hopkinson, F., “Account of a Worm in the Horse’s Eye,” from ‘Trans. of Amer. Phil. Soc.,’ in ‘Med. Comment.,’ vol. xi, p. 166, 1784.--Hutchinson, J., “Hydatid in the Eye of a Horse,” ‘Path. Soc. Trans.,’ and rep. in ‘Lancet,’ 1857.--Huxley, “On Echinococcus (from the Zebra),” see Bibl. No. 20, o.--Jeaffreson, W., “Case of Removal of a Worm from the Eye of an Arab Horse,” ‘Lancet,’ p. 690, 1836-37, and ‘Veterinarian,’ p. 471, 1837.--Kennedy, M., “Account of a Nondescript Worm (Ascaris pellucidus) found in the Eyes of Horses in India,” ‘Trans. Roy. Soc. Edin.,’ vol. xi, p. 107, 1816.--Kirkman, ‘Hydatids’ (see Bibl. No. 20, o).--Knox, ‘Edin. Med. and Surg. Journ.,’ 1836.--Krabbe (l. c., in text).--Lee, C. A., “On Filaria papillosa in the Anterior Chamber of the Eye of a Horse (and on Filariæ in general, &c.),” ‘Amer. Journ. Sci. and Art.,’ vol. xxxix, p. 278, 1840.--Lessona, G., “On the Bot (or Œstrus) of the Horse,” from ‘Recueil de Méd. Vét.,’ in ‘Veterinarian,’ p. 156, 1854.--Leuckart (l. c., in text).--Litt, W., “A Singular Case (of an immense number of Worms in a Colt),” ‘Veterinarian,’ p. 529, 1852.--Macnamara, “On F. papillosa in the Eye of Man and the Horse,” ‘Indian Ann. Med. Sci.,’ 1864.--Marcet (see Bibl. No. 34).--Mead, J., “A Worm in the Scrotum of a Colt,” ‘Veterinarian,’ 1843, p. 648.--Mégnin, “Petit Tænia inorme du Cheval,” in ‘Bull. de la Soc. Cent. de Méd. Vét.,’ t. vi, 3e série, p. 112.--Idem, ‘Monog. de la tribu des Sarcoptides,’ &c.; see also review by myself in the ‘Veterinarian,’ Aug., 1877.--Mercer, J., “On Entozoal or Worm-aneurism,” ‘Lond. Med. Gaz.,’ 1847, and in part x of “Contrib. to Zool. Path.,” in the ‘Veterinarian,’ p. 33, 1846.--Meyrick, J., “Death of a Colt from Entozoa within the Abdomen,” ‘Veterinarian,’ 1859, p. 695.--Moir, J., “Rupture of the Ileum resulting from Worms,” ‘Veterinarian,’ 1857, p. 265.--Molyneux, R., “On Worm in the Eye of Horses in India,” ‘Veterinarian,’ 1828, p. 309.--Morgan, A., “Case of Hydatid in the Brain of a Mare,” ‘Veterinarian,’ p. 396, 1855.--Numan, A., ‘Ueber die Bremsen Larven, im Magen der Pferde,’ 1837.--Idem, “Entozoon (Monostoma settenii) from the Eye of a Horse,” from ‘Tidschr. voor naturl. Geschied. en Physiol.,’ 1842, in ‘Med.-Chir. Rev.,’ 1842.--Idem (for remarks on Cysticercus fistularis), ‘Over den veelkop blaasworm’ (l. c., Bibl. No. 49), p. 263.--Peall, T., “A Discourse on ‘Worms,’” at p. 37, in his ‘Observations, chiefly practical, on some of the more common Diseases of the Horse,’ pub. at Cork, 1814.--Percivall, C., “Worm in the Eye of the Horse (two cases),” ‘Veterinarian,’ p. 75, 1828.--Percivall, J., “A Case of Ascarides in the large Intestines of the Horse,” ‘Veterinarian,’ p. 358, 1829.--Poulton, T. J., “Large numbers of Parasites in the Intestines of a Mare,” ‘Veterinarian,’ 1866, p. 385.--Seaman, J., “Worms in the Blood-vessels of Horses and Colts,” ‘Edin. Vet. Rev.,’ 1864, p. 520.--Simonds, “On Disease of the Mesenteric Artery, produced by Strongyli,” ‘Path. Soc. Trans.,’ 1854.--Skeavington, G., “On Worm in the Eye of the Horse (three cases),” ‘Veterinarian,’ 1834, p. 196.--Sonsino, P., “On the Entozoa of the Horse in relation to the late Egyptian Equine Plague,” ‘Veterinarian,’ Feb. and March, 1877.--Tyndal, J., “Worms in the Intestines of a Mare,” ‘Veterinarian,’ 1843, p. 629.--Twining, W., “Obs. on the Filaria or Threadworm found in the Eyes of Horses in India,” ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. i, p. 345, 1825; rep. in ‘Veterinarian,’ p. 114, 1828.--Valenciennes, “On the Spiroptera megastoma of Gurlt,” abstract of a paper from Acad. Sci. of Paris, reported in ‘Lancet,’ 1843.--Varnell, “Remarks on Cases of Parasitic Disease in Horses,” ‘Veterinarian,’ p. 201, 1864.--Veret, “Perforation of the small Intestines by Ascarides lumbricoides (in the Horse),” from ‘Rec. de Méd. Vét.,’ in ‘Veterinarian,’ p. 569, 1837.--Vincent, “Curious case of Incurable Lameness from Hydatids,” ‘Veterinarian,’ 1848, p. 674; see also p. 3, ibid.--Wallis, “Note on the occurrence of (250) Lumbrici in a Horse,” ‘Veterinary Record,’ 1849, p. 300.--Walters, R. G., “Parasites in the Kidneys of a Mare,” ‘Veterinarian,’ 1866, p. 265.--Woodger, “Hydatid in the Brain of a Horse,” ‘Veterinarian,’ 1863, p. 75.--Woods, J. S., “Tetanus in a Mare, associated with the Larvæ of Œstrus equi within the Stomach and Duodenum,” ‘Veterinarian,’ 1859, p. 693.--Wright, “Strongyli in the Scrotum of a Colt,” ‘Veterinary Record,’ 1849, p. 385.--Youatt, “Worms between the Tunics of the Stomach,” ‘Veterinarian,’ 1835, p. 571.--Idem, “Tetanus, Worms in the Trachea, and Dilatation of the Heart, in a Zebra,” ibid., p. 504, 1836.--Idem, “Worms in the Nasal Cavity of the Horse,” ibid., p. 329, 1832.--Zangger, “Remarks on Entozoa,” from the French, ‘Veterinarian,’ 1855, p. 463.

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X. (PACHYDERMATA)

Concerning the parasites and parasitic diseases of this miscellaneous assemblage of large mammals, I shall first speak of those of the proboscideans (Elephantidæ). Except by myself, they have been but little studied, and I am yet waiting for an opportunity to give further time to their consideration. When Diesing published his ‘Systema’ only two helminths were referred to the Indian elephant, namely, Ascaris lonchoptera and an undescribed fluke supposed to be a distome. The whole subject requires revision, but I think the following species must, for the present at least, be allowed recognition:--Fasciola Jacksoni (mihi), Amphistoma Hawkesii (mihi), Ascaris lonchoptera (Diesing), Sclerostoma Spinuliferum (Baird), and Dochmius Sangeri (mihi). Either the Ascaris or the Sclerostoma is probably identical with Rudolphi’s Strongylus elephantis.

At the Norwich Meeting of the British Association, in 1868, I exhibited two flukes received from J. S. Thacker, V.S., of the Madras Army. They were handed to me by the late Dr Baird, and were labelled “Distoma taken from liver of elephant and forwarded for classification.” I stated at the time that these entozoa were identical with certain flukes previously obtained from the duodenum and biliary ducts of an Indian elephant, and which, though carefully preserved in the Boston Museum, U.S., had never been properly described. They were only briefly noticed by Dr Jackson in his ‘Descriptive Catalogue’ of the Museum. In the summer of 1868 fifteen specimens of fluke, removed from Burmese elephants, had been forwarded to and received by Professor Huxley from Rangoon, accompanied by a statement to the effect that they were the cause of an extensive and fatal disease in Burmah. Through the kindness of Prof. Huxley I was allowed to make use of his specimens for the purpose of comparison and identification, and thus it became evident that our specimens were of the same species. It was also evident that the species could be none other than that represented by the Boston specimens. Further examination having made it clear that the organisation of these flukes departed from the ordinary distome type, I named the parasite Fasciola Jacksoni, at the same time offering the following description (‘Entozoa,’ Supp., 1869, p. 80):--“Body armed throughout with minute spines, orbicular, usually folded at either end towards the ventral aspect, thus presenting a concavo-convex form; oral sucker terminal, with reproductive papillæ about midway between it and the ventral acetabulum; intromittent organ 1/4″ in length; digestive apparatus with two main zigzag-shaped canals, giving off alternating branches at the angles thus formed, the ultimate cæcal ramifications occupying the whole extent of the body; length, when unrolled, from 1/2″ to 5/8″, breadth 1/3″ to 1/2″.” Now, if reference be made to the appendix of the late C. M. Diesing’s ‘Systema Helminthum,’ it will be found that Jackson’s statement had not escaped that helminthologist’s notice, though, not having seen any specimens, he was not unnaturally led to place the species amongst the distomes proper. In Diesing’s subsequently published ‘Revision der Myzelminthen,’ the species is formally characterised as the Distomum elephantis of Jackson (‘Sitzungsberichte d. Math.-nat. Cl. d. k. Akad. d. Wissenchaften,’ Bd. xxxii, 1858). In my “Synopsis of the Distomidæ,” which appeared in the ‘Journal of the Linnean Society’ for 1861, I had also placed it amongst the distomes, not considering it to be a doubtful form (‘Proceed. Linn. Soc.,’ “Zoology,” vol. v, p. 9). These references exhausted the literature of the subject up to the time of the issue of my ‘Manual’ in 1873, where this fluke is again briefly noticed (p. 13). Several of Prof. Huxley’s specimens have been added to the entozoological department of the Hunterian Museum. It is clear that all these notices and descriptions point to the same parasite. The worm has since been more carefully described by Dr R. H. Fitz, from a series of dissections and preparations made by Dr H. P. Quincy, and deposited in the Warren Museum, Boston, U.S.

About the middle of June, 1875, I received a letter from General Hawkes, of the Madras Staff Corps, dated Secunderabad, May 12th, 1875, and in reference to the subject before us he writes as follows:--“My attention has been recently directed to a very unusual mortality of elephants at this station. Out of twenty-eight elephants under my charge, no less than twelve have died within the last sixteen months, whereas the average annual mortality has been hitherto only two per annum out of thirty-eight in our establishment. In every case of death there appeared to exist serious organic disease quite sufficient to account for such death, but as the mortality increased I had a post-mortem examination made in each case; and although here also organic disease sufficient to account for death was present in each case, yet in every one of these elephants we found the liver-fluke in greater or less abundance.” General Hawkes adds:--“Meanwhile I have sent you a small box containing three bottles, one containing the liver-fluke (Fasciola Jacksoni) referred to in your work on the parasites of domesticated animals. It seems possible that the other two species of parasites may not have been brought to your notice. Both of these, namely, the “masuri” and the “soorti,” are very common in elephants. They are both found in the intestines only. The “masuri,” when present in any quantity, cause considerable disturbance, and the animal instinctively resorts to the eating of earth, which it consumes in large quantities until the bowels are acted on and the worm expelled. The soorti is more common than masuri, and does not seem to inconvenience the animal very much. When expelled from the animal the soorti is a round white worm, like most of the threadworms; the masuri, on the other hand, is of a delicate flesh color.” Shortly after the receipt of this letter I obtained the entozoa in a good state of preservation. Accordingly I wrote to General Hawkes, stating that the flukes were clearly referable to Fasciola Jacksoni; that the parasites to which the natives of Hindostan apply the term “soorti” were evidently examples of Ascaris lonchoptera (Diesing), previously called strongyles by Rudolphi; and that the worms which he called “masuri” were trematodes new to science. I named the species Amphistoma Hawkesii, in honor of the donor. The bottle contained as many as forty-nine specimens. I may here remark that I have made inquiries of the keepers of the elephants at the Zoological Gardens as to whether they have ever seen entozoa that were passed by the animals under their care. They replied in the negative, the keeper of the African elephants (Scott) having made frequent inspection of the fæces. I was the more anxious to secure information on this point since, during my frequent visits to the menagerie, I had observed that the African elephants were in the habit of swallowing large quantities of mud and dirt from small hollows in the ground near the great water-tanks in which they bathe. Prof. Garrod (who had dissected three elephants) also assures me that there has been no trace of an entozoon in any of the Indian elephants examined by him. In one dissected at Edinburgh the same negative result was obtained. From the facts at present in my possession, I conclude that the habit of earth-eating, displayed alike by Indian and African elephants (and, as stated in my account of the equine parasites, shared by horses), is not necessarily due to the presence of parasites. I apprehend rather, that it is resorted to by these animals under any circumstances of intestinal irritation, whether created by entozoa or other foreign agents. The notion of the elephant’s intelligent self-cure by eating earth is a very old fable. Captain Forsyth, as quoted by Mr Fleming, alludes to it in his ‘Highlands of Central India,’ and I find the same ideas recorded by Williamson and Howitt. Forsyth says:--“Elephants are very liable to intestinal worms. They generally cure themselves by swallowing from ten to twenty pounds of earth.” Captain Williamson says:--“They are much troubled with worms, for the cure of which the elephant eats earth. If the dung be inspected there will be seen an amazing number of moving objects, which much resemble pieces of chewed sugar-cane.” Some excellent practical remarks are added, testifying to the value of the native remedy called Kallah-nimok, or bit-noben, which is a saline purgative. In Lieut. Ouchterlony’s essay (quoted below) no allusion is made to the subject of worms.

General Hawkes afterwards supplied me with further information. In a letter from Secunderabad, dated July 30th, 1875, he says:--“As regards the liver-fluke (F. Jacksoni), it appears from your treatise to have been first observed in 1847. The only other published notice that I have been able to find of it is contained in a letter to a newspaper, dated ‘Rangoon, 16th July, 1867,’ and is signed ‘R. B.’ In this letter the unusual mortality of seven elephants in about fifteen days is attributed to the presence of this liver-fluke, the two other parasites (Amphistoma and Ascaris lonchoptera) being also present in the intestines.” “Now (continues General Hawkes), in every case at which I was present flukes were found in greater or less numbers in the gall-ducts of the liver, and the Amphistoma was also as constantly present in the intestines, the soorti (Ascaris lonchoptera), contrary to the general experience of the elephant attendants, being less frequently met with, though from its color and slender shape it is not so easily detected among the huge mass of fæces as the larger Amphistoma.” Speaking of the amphistoma General Hawkes says:--“This internal parasite is well known to all who possess elephants. It is alluded to by Dr Gilchrist in his treatise on the ‘Diseases of Elephants,’ first published in 1841, but he merely mentioned it under its local name, masuri, and made no attempt either to describe it scientifically or to ascertain its place in the natural system. As far as my experience goes it is only found in the intestines. These parasites appear to be very generally present in the elephant. When their numbers are few the ‘host’ is probably not much inconvenienced, but when present in any great quantity they undoubtedly cause much irritation. When this is felt, the animal, as before remarked, instinctively resorts to a simple and effectual remedy. He eats a quantity of earth, which purges him thoroughly and expels the amphistoma. The mahawats are of opinion that whilst the elephant is eating earth to relieve himself of the pests the daily allowance of rice should be scrupulously withheld; and they say that if the rice, which is given uncooked, is eaten by the animal under these circumstances, excessive purgation is induced, which frequently results in death. How far this opinion is founded on fact I am unable to say, but the mahawat’s name for this disease means ‘fasting,’ and bears testimony to the generally received notion of the necessity of withholding the rice when the animal is eating earth.”

When describing the parasites of the horse (p. 358), I spoke of Collins’ amphistome from that animal, but in the letter addressed to me from Simla, 22nd March, 1875, Mr. Collins made no allusion to the earth-eating habit. He wrote:--“I forward you by this mail parasites found in the colon of a horse that died, a subject of fever peculiar to this country. There were about a thousand of the parasites, and nearly the whole of them were situated close to the cæcum, and were loose in the gut. Not having seen parasites at all similar to these, I have forwarded them for identification. They were of a brick-red color when first obtained.” These explicit statements by Mr Collins are interesting from many points of view. One has only to place his specimens side by side with those from the elephant in order to satisfy one’s self that the two forms are distinct. For the reasons already stated I provisionally called the worm Amphistoma Collinsii. It is probable that other veterinary surgeons have encountered this entozoon in India; but, unless they can point to some published account of the fact, Mr Collins is entitled to be considered as its discoverer. Doubtless many other European residents in India, Ceylon, and Burmah, must, like Dr Gilchrist, be well acquainted with the masuri as such, though unaware of their zoological position.

In a record of the post-mortem examination of one of the victims of the Secunderabad epizoöty, the veterinary surgeon said:--“No doubt disease of the lungs and subacute inflammation of the bowels were the immediate cause of death, but the large number of flukes in the liver and the intestinal parasites (i. e. the amphistomes) account in a great measure for some of the symptoms shown, and these symptoms accord in many respects with those shown in elephants that died in Burmah during the epizoöty (rot) in 1867, as recorded by R. B., notably, refusal of food, standing with mouth open, restlessness, and puffiness about the head and shoulders. The liver parasite is no doubt the same referred to by R. B., and is that termed by Dr Cobbold Fasciola Jacksoni.” In reference to a later case the same officer remarks:--“I carried out the post-mortem examination with special reference to inquiry as to the probability of the mortality amongst elephants at this station being of parasitic origin. This was suggested to me by the former case. The post-mortem appearances differed in every respect. There were flukes in the liver, but in no great quantity, and the structure of the liver was sound. Although not assisted by this case in attributing the mortality to parasitic origin, I am strengthened in my opinion that the death of the previous elephant was due to disease caused by the presence of the liver fluke.” This report, by Mr W. S. Adams, is to some extent in harmony with later information. An epizoötic outbreak amongst elephants has occurred in England, at Sanger’s Circus, and I had opportunity to examine one of the dead animals. In my own opinion, and in that of Mr F. Smith, the veterinary surgeon who attended the animals professionally, the disease was due to parasites. I obtained large quantities of Amphistoma Hawkesii from the intestinal canal, and also other worms. The death of one of the elephants was made the subject of litigation, when, as might be expected, great diversity of opinion as to the cause of the fatal issue prevailed.

Mr Smith, an old pupil of mine, regarding the amphistomes and strongyles as the cause of death, wrote to the effect that “some of the worms were found between the coats of the intestine, and others on the free surface of the gut, whilst the excretory ducts of some of the glands were found blocked with them.” The animal examined by myself on the 24th of August, 1876, yielded numerous examples of Amphistoma Hawkesii, Ascaris lonchoptera, and Dochmius Sangeri, the last species being so named by me after the owner of the circus who lost the herd of elephants by the epizoöty. The male Dochmii measured 5/8 and the females 3/4 of an inch in length. Here I must reluctantly quit the helminths of elephants, adding only an expression of surprise that Dr Max Schmidt should have had so little to say concerning them in his otherwise instructive memoir on ‘The Diseases of Pachyderms’ (quoted below).

I have but a few words to offer respecting the ectozoa. A species of mite has been described whose generic position appears doubtful. I allude to Homopus elephantis of Fürstenberg, or Symbiotes elephantis of Gerlach. According to Mégnin it is a nymphe adventive or hypope of a variety of Tyroglyphus siro. This acarus is abundant in old forage. Another ectozoon is Hæmatomyzus elephantis. It differs from the lice proper in many respects, but, according to Piaget, the reproductive organs resemble those of Hæmatopinus. In ‘Science Gossip’ for June, 1871, Mr H. C. Richter describes “a new form of parasite,” which is called Idolocoris elephantis. The insect, which was one line in length, was found upon an elephant in Ceylon. According to Walker it not only constituted the type of a new genus, but of an altogether new family of the Hemiptera Heteroptera, coming very near to the bed-bugs (Acanthidæ). It is a huge sucking louse. From the discussion which followed, it seems that the parasite had several times been seen before, and was none other than E. Piaget’s Hæmatomyzus elephantis. Excellent figures accompany Richter’s and Piaget’s descriptions. Notwithstanding Piaget’s explanation, I think the specific name, longirostris, would have been a more appropriate appellation.

BIBLIOGRAPHY (No. 51).--(Anonymous), “Diseased Elephants,” see ‘Lancet,’ Sept. 2, 1876; also “Report of the Case at Law (Jamrach v. Sanger),” given in the ‘Veterinarian,’ Dec., 1877, p. 886.--Cobbold, T. S., “Description of a species of Trematode from the Indian Elephant, with remarks on its Affinities,” ‘Quart. Micros. Journ.,’ Jan., 1869; see also ‘Entozoa,’ supp., 1869, p. 80.--Idem, “On the Destruction of Elephants by Parasites, with remarks on two new species of Entozoa and on the so-called Earth-eating habits of Elephants and Horses in India,” ‘Veterinarian,’ Oct., 1875.--Idem, “Further Remarks on Parasites from the Horse and Elephant, with a notice of new Amphistomes from the Ox,” ibid., Nov., 1875.--Diesing (l. c., in text).--Fitz, R. H., “Anatomy of Fasciola Jacksoni,” ‘Rep. of Boston Soc. Med. Sci.,’ in the ‘New York Med. Journ.,’ Nov., 1876.--Fleming, G., “The Diseases of Elephants” (chiefly from Captain Forsyth’s work on the ‘Highlands of Central India’), ‘Veterinarian,’ March, 1873, p. 181.--Mégnin, “Mém. sur les Hypopes,” in Robin’s ‘Journ. de l’Anat. et de la Physiol.,’ 1874 (H. elephantis), p. 248.--Ouchterlony, J. W., “An Essay on the Management of the Elephant, and its Treatment in ordinary Diseases,” ‘Rep. of Vet. Med. Assoc.,’ Nov., 1872, and pub. in ‘Veterinarian,’ Jan., 1873, p. 65.--Piaget, E., “Description d’un parasite de l’éléphant,” ‘Tijschrift voor Entomologie,’ 1869, p. 249.--Richter, H. C., “A new form of Parasite (Idolocoris elephantis),” ‘Science Gossip,’ 1871, pp. 131, 185, 211, 278.--Schmidt, Max, “Die Krankheiten der Dickhäuter,” ‘Deutsche Zeitschrift f. Thiermed. und vergleichende Pathologie,’ f. Nov., 1878, s. 360.--Williamson, T., ‘Oriental Field Sports,’ London, 1807, vol. i, p. 138.

The parasites of the Rhinoceridæ have been even less studied than those of elephants. In 1856 Prof. Peters described a tapeworm from Bruce’s rhinoceros (R. Africanus), which he named Tænia gigantea. In 1870 Dr Murie, under the provisional name of T. magna, published a description of the strobile of the same cestode from an Indian rhinoceros (R. unicornis). From a total misconception of the character of the proglottides, Murie was led to suppose that the segments of the strobile were very deep as well as broad; whereas the proglottids are remarkably narrow, thus partaking of the characters of the Tæniæ of the larger herbivora in general. In a subsequent paper Peters pointed out these errors. Murie had, in fact, rolled several segments into one. In 1877 Professor Garrod encountered the same cestode in Rhinoceros sondaicus, and, following Peters’ example, separated it from the Tæniæ proper (Plagiotænia gigantea). The idea of generically separating tapeworms possessing a more or less striking breadth of strobile is not one which commends itself to my view, seeing that many of the tapeworms of herbivora closely resemble the rhinoscerine cestodes in this respect. As Diesing hints, this tapeworm comes near to T. perfoliata, but Garrod’s and Peters’ figures both show that Plagiotænia wants the neck-lobes. The presence of cephalic appendages may be regarded as generically distinctive, but it does not appear that Blanchard separated the perfoliate tapeworm of the horse from the Tæniæ proper on this ground. Therefore, in my account of the equine tapeworms, I have not adopted his genus Anoplocephala. I may remark, in passing, that if the distinctions, as between armed and unarmed, or between proboscis-bearing (Rhynchotæniada) and non-proboscis-bearing tapeworms (Arhynchotæniada), are to be maintained, they should be expressive of divisional or subordinate value. Dr Weinland’s arrangement, having reference to the thick- and thin-shelled ova (Sclero- and Malaco-leptidota), is, perhaps, preferable. The whole subject of classification requires revision, but it should be undertaken by some helminthologists practically acquainted with a large number of cestode types. As Garrod has well observed, Plagiotænia enjoys a wide geographical distribution, infesting alike Indian and African hosts. Prof. Garrod, I observe, speaks of the head of the mature tapeworm as the scolex--an extension of the meaning of a term not usually recognised. In this, however, he only follows Peters’ unfortunate example.

The wide distribution enjoyed by Peters’ Plagiotænia is probably equalled by that of the rhinocerine stomach-bot (Gastrophilus rhinocerontis, Owen). This parasite was originally described in 1840, and since that time it has been frequently encountered both in India and Africa. To Mr Spooner Hart, of Calcutta, I am indebted for a large number of specimens; their size exceeding that of any other bots that have come under my notice. Probably this parasite infests the stomach of rhinoceroses generally; at all events, it occurs in R. unicornis, R. bicornis, and R. simus. At present the imago is unknown. The longest larvæ in my possession measure 1-1/8″, but Brauer records specimens up to 35 mm. in length by 10 mm. in thickness. In African hosts M. Delegorgue found these parasites in prodigious numbers.

BIBLIOGRAPHY (No. 52).--Brauer, “Bot of the Rhinoceros,” ‘Monogr. der Œstr.,’ 1863, s. 92.--Cobbold, “Note on Parasites presented by Messrs Danford, Hart, and others,” ‘Veterinarian,’ 1875, p. 513.--Coquerel and Sallé, in ‘Ann. Soc. Entom. de France,’ 1862 (quoted by Brauer).--Delegorgue, ‘Voyage dans l’Afrique’ (quoted by Brauer).--Garrod, “On the Tænia of the Rhinoceros of the Sunderbunds (Plag. gig., Peters),” ‘Proc. Zool. Soc.,’ Nov. 20, 1877, p. 788.--Hope, in ‘Trans. Entom. Soc.,’ 1840, p. 259.--Joly, M. N., “Recherches Zool. (&c.) sur les Œstrides (&c.),” in ‘Ann. des Sciences (&c.) de Lyon,’ 1846 (quoted by Brauer).--Murie, J., “On a probably new species of Tænia (T. magna?) from the Rhinoceros,” ‘Proc. Zool. Soc.,’ 1870, p. 608.--Peters, W., “Note on the Tænia from the Rhinoceros, lately described by Dr J. Murie,” ‘Proc. Zool. Soc.,’ 1871, p. 146.

Very little has been written respecting the parasites of the Hippopotamidæ and Tapiridæ. I think it was Livingstone who first drew attention to the fact that the river-horse or sea-cow is much infested by tapeworms, but I have not seen any published description of the worm. Dr. Murie, during his sojourn in Egypt, found a solitary bot embedded in the soft parts surrounding the eye, and judging from his figure the species is new to science. Provisionally I speak of it as the Hypoderma Muriei. In the paper (quoted below) Murie appends a list of all the animals in which bots have been found. Though chiefly taken from Brauer, it is useful and tolerably complete. So far as I am aware no cestodes have been described as infesting tapirs; nevertheless, at least five other kinds of helminth have been found in Tapirus Americanus. Of these, two are flukes (Amphistoma asperum and A. pyriforme), and three are nematodes (Sclerostoma monostechum, Spiroptera mediospiralis, and Sp. chrysoptera). The three species first named occupy the cæcum, whilst the others are found in the stomach. According to Molin’s description, both species occupy tuberous excrescences of the mucous membrane, thus reminding us of the similar habit enjoyed by Sp. megastoma in the horse. The Sp. chrysoptera is a comparatively large species, the males measuring an inch, and the females as much as an inch and a half in length. Both of the spiropteras were obtained from tapirs by the indefatigable Natterer, Sp. mediospiralis being also procured by him from the aguti. If I have read Molin correctly, as many as thirty-four examples of S. mediospiralis were taken from a single excrescence in the stomach of the tapir. Upwards of a hundred specimens were procured, collectively, from three similar stomach-excrescences in Dasyprocta aguti. These, and the other tapirine parasites above mentioned, were originally discovered in Brazil.

BIBLIOGRAPHY (No. 53).--Diesing, “Neue Gattungen von Binnenwürmen nebst einem Nachtrage zur Monographie der Amphistomen,” in ‘Annalen d. Wien. Museums,’ Feb., 1839, s. 236.--Idem, ‘Systema,’ Bd. ii, s. 306.--Molin, “Una monografia del genere Spiroptera,” in ‘Sitzungsb. der math.-naturw. Cl. d. k. Akad. d. Wissensch.,’ Bd. xxxviii, s. 1001, 1859.--Murie, “On a larval Œstrus found in the Hippopotamus,” ‘Proc. Zool. Soc.,’ 1870, p. 78.

The osculant position of the anisodactyle pachyderms (Hyracidæ), formerly classed as rodents, renders it desirable that their parasites should be briefly noticed in this place. Probably these animals, zoologically speaking, come nearest to the rhinoceroses, but Prof. Owen showed that, anatomically, they possessed marked affinities with the sloths. The klipdas or dasse (Hyrax capensis) is infested by a tapeworm, of which hitherto the proglottides only appear to have been seen (Tænia hyracis, Pallas). Under the name of Cœnurus serialis a larval cestode has been described by Gervais, the same parasite being called Arhynchotænia critica by Pagenstecher (“Zur Naturgeschichte der Cestoden,” in ‘Sieb. u. Köll. Zeitschrift’). A variety of nematodes have also been observed in the Cape hyrax. Of these, the so-called Physaloptera spirula is classed as doubtful by Molin and Diesing. Hemprich and Ehrenberg furnished brief descriptions of four other nematodes. Two of these worms were placed in the genus Oxyuris (O. pugio and O. flavellum), and the other two in the new genus Crossophorus, which they formed for their reception (C. collaris and C. tentaculatus). The whole of these nematoids were obtained either from the cæcum or large intestine.

An able article in the ‘Natural History Review’ for July 1865, attributed to Professor Huxley, expressed very clearly the popular notion as to the great danger of the flesh of swine considered as a source of human parasites. No doubt the filthy pachyderms in question (Suidæ) are much infested by helminths, some of which gain access to man, but swine are neither attacked by a greater variety of entozoa than other domesticated animals, nor are they so frequently a source of human tapeworms as cattle. In the article above quoted the following passage occurs:--“Of all animals, feral or domestic, the common pig is beyond all doubt the most fertile source of human entozoa; at least, of important parasites, Trichina spiralis and the tapeworm would, there is good reason to believe, cease to infest us, did not this favorite quadruped act the part of a communicating medium.” This paragraph was evidently written under the impression that “the tapeworm” most commonly found in man was derived from the hog. So far back as 1864 I showed that this was an entire mistake.

Flukes are rare in swine; nevertheless, Fasciola hepatica and Distoma lanceolatum are occasionally present in the domestic hog, and the peccaries (Dicotyles) are infested by an Amphistome (A. giganteum). This large species, 3/4″ in length, formed the basis of an admirable account of the anatomy of this genus of worms which the learned Vienna helminthologist, Diesing, wrote before he was deprived of his eyesight. The merits of that respected systematist’s investigations have, I think, been much underrated, in consequence, no doubt, of the artificial character of his system of classification. For all that, his writings remain invaluable. Turning to the cestodes of swine, there is not, so far as I am aware, any evidence of the occurrence of sexually-mature tapeworms either in the hog or its allies; but the frequency of larval cestodes, known as measles (Cysticercus telæ cellulosæ), was well known to the early Jewish writers. In the first part of this work I devoted as much space as I could spare to the consideration of Cysticerci in general, and the pork-measle in particular; but an exhaustive knowledge of the subject in relation to hygiene can only be acquired by consulting the principal original memoirs (quoted in the Bibliographies Nos. 13 and 14). In a Westphalian ham, part of which was sent to me for examination, I calculated that each pound of the flesh must have contained upwards of 600 Cysticerci. I was informed by the donor, Dr Prior, that in spite of the disgusting state of the meat much of it had been eaten by the well-to-do family who purchased the ham. Cysticerci occasionally occupy the brain of the pig in considerable numbers. Florman recorded a case of this kind where their presence gave rise to vertigo in all respects resembling the gid ordinarily produced by Cœnurus in the sheep. As regards the larger cestode larvæ, Cysticercus tenuicollis and Echinococcus veterinorum are of frequent occurrence. One not unfrequently encounters the former in the mesentery, whilst the liver of the hog is sometimes so crowded with hydatids that scarcely any of the glandular substance of the organ remains visible. It is surprising how little the infested bearers appear to be inconvenienced in such cases. In the winter of 1859, and in the autumn of 1860, I found large cystic entozoa in an African Wart-hog and in a Red River hog. These animals had died at the London Zoological Society’s Menagerie; and as the worms appeared to me at the time to be quite distinct from the ordinary slender-necked hydatid, they were named, respectively, Cysticercus phacochæri æthiopici and C. potamochæri penicillati. The solitary example from the wart-hog was found in a cyst near the colon; whilst of the five large bladder-worms obtained from the Red River hog, one infested the liver and the other four were lodged in the folds of the mesentery. The caudal vesicle of the worm from the wart-hog measured 3-1/2″ in diameter, the vesicle of the other bladder-worm being much longer. A reference to the original figures will show that these forms are distinct. Swine are largely infested by nematodes. The best-known form is Ascaris lumbricoides, which Dujardin regarded as distinct (A. suilla). The hitherto disputed identity of this worm with the human lumbricoid being no longer questionable, the importance of the entozoon in relation to lumbricoid endemics must at once be obvious; I have already, however, dwelt upon this subject when treating of the human parasites. In like manner, the subject of the flesh-worm disease, which is due to Trichina spiralis, cannot be discussed in this place, as I have fully entered upon it in connection with trichinosis in the human subject. What may be the nature of the small threadworms found by Leidy in the extensor muscles of the hog I cannot say, but Diesing inferred that they might represent a distinct species (Trichina affinis). As regards the allied genus Trichocephalus, the common species infesting swine (T. crenatus), appears to be rarely absent. It not only infests the common domestic and wild hog, but the peccaries and wart-hogs. These entozoa are probably harmless to their bearers. In reference to them Krabbe says:--“When the eggs are expelled with the excrement and pass into water, then the embryos, after several months’ furlough, and there undergoing further development, are transferred to the swine’s intestinal canal.” If I rightly understand the paragraph (‘Husdyrenes Indvoldsorme,’ p. 28), Krabbe states that the embryos are still within their egg-coverings when infection takes place. The maw-worm of the hog is known as Spiroptera strongylina. It was described and figured by Gurlt. The males measure 1/2″ and the females 3/4″ in length. Specimens of this worm were supposed to have been found by Natterer in Dicotyles albirostris; but it seems that the worms in question represent a distinct species, if not an altogether new genus. In the year 1864 Professor Simonds placed in my hands a very singular nematode, to which I gave the binomial term Simondsia paradoxa. Numerous examples of this worm were found by Prof. Simonds occupying cysts within the walls of the stomach of a hog which had died at the London Zoological Society’s Menagerie. In my introductory treatise I wrote of it as follows:--“The worm in question has been regarded by Mr Simonds as a species of Strongylus, but I am inclined to think that its affinities will place it nearer to the genus Spiroptera. At present I have only examined the female, which is characterised by the possession of a multitude of large tentacle-like appendages surrounding the neck. These processes, by their aspect, remind one of the so-called branchial projections on the back of Eolis, but in this worm I believe them to be special folds formed for the lodgment of unusually developed uterine organs. The female worm is about 3/4″ in length.”

In the interval that has elapsed I have been unable to supply further particulars, and unfortunately the original drawings of the worm have been lost. The habits of the parasite remind us of Spiroptera megastoma infesting the walls of the stomach of the horse. Not improbably this singular entozoon may turn out to be identical with Molin’s Spiroptera sexalata, and if so, it may correspond with Spiroptera strongylina. However, Diesing afterwards recognising, as I had done, the desirability of separating this last-named worm from the Spiropteræ proper, formed for it his new genus Physocephalus. He then called the worm Physocephalus sexalatus. If, as is probable, my Simondsia and Diesing’s Physocephalus are identical, the species found by Simonds ought to be recognised by the generic title which Diesing proposed. His genus was established about four years before I described my Simondsia. Diesing was evidently led up to the recognition of the generic distinction of the worm by Molin’s examination and description of the worm. As, in my original account of the worm found by Simonds, I spoke of numerous appendages to the neck, it is evident that further investigation is necessary to clear up the question of identity. According to Molin and Diesing the male Spiroptera sexalata measures rather beyond 1/4″ and the female beyond 1/2″ in length. Neither Diesing nor Molin speak of Natterer’s worms as being found encysted. In fact they were free. Molin simply remarks:--“Io ne esaminai in oltre 6 esemplari maschi e 77 femine raccolti in parte dal muco che revestiva le pareti dello stomaco, ed in parte dal pasto contenuto nello stesso organo di un Dicotyles albirostris femina ai 24 Aprile, 1826.” After all that has been said it may be that my Simondsia paradoxa and Diesing’s Physocephalus sexalata are quite distinct, and that like the large- and small-mouthed maw-worms of the horse (Spiroptera megastoma and S. microstoma) they play a corresponding rôle. Before very long I hope to set this question definitively at rest.

Passing to the strongyloid nematodes one of the most remarkable and important species is Stephanurus dentatus. In the ‘Annalen des Wiener Museums’ for 1839 (s. 232) this worm was first described by Diesing, who employed the generic title as expressive of the crown-like figure of the tail of the male worm. Diesing wrote as follows:--“At Barra do Rio Negro, on the 24th of March, 1834, Natterer discovered this peculiar genus of worms occurring singly or several together in capsules situated amongst the layers of fat in a Chinese race of Sus scrofa domestica. The males measure from ten to thirteen lines long, the females from fifteen to eighteen lines, the former being scarcely a line in breadth at the middle of the body, whilst the latter are almost a line and a half in thickness. The curved body thickens towards the tail, is transversely annulated, and viewed with a penetrating lens is seen to be furnished with integumentary pores. The oral aperture opens widely. It is almost circular, and is supplied with six teeth at the margin. Two of these standing opposed to one another are larger and stronger than the rest. The tail of the male, when spread out evenly, is surrounded by a coronet of five lancet-shaped flaps; the combined flaps being connected together from base to apex by means of a delicate transparent membrane. The single spiculum situated at the extreme end of the tail projects slightly forward and is surrounded by three skittle-shaped bodies. The tail of the female is curved upon itself, rounded off, and drawn out at the extreme end into a straight beak-shaped point; whilst to both sides of the stumpy caudal extremity of the body short vesicular prominences are attached. The female reproductive outlet occurs at the commencement of the second half of the body. Thus, judging by its external characters this genus is most closely allied to Strongylus.” In reproducing Diesing’s description I have here rendered the translation somewhat more freely than in my previous record of the discovery given in ‘Nature’ (1871). The original description is supplemented by a brief account of the internal anatomy of the worm.

So far as I am aware no subsequent notice of this entozoon appeared until the year 1858, when Dr J. C. White gave some account of a “find” made in the United States. This re-discovery was reported in the sixth volume of the ‘Proceedings of the Boston Natural History Society.’ Dr White says:--“The worms were found in the leaf-yard of an apparently healthy hog, in the adipose tissue near the kidney. They occupied a space of the same about the size of a man’s fist and had burrowed through the mass in every direction, forming canals three or four millimètres in diameter, which terminated in cysts. On cutting open these cavities, which did not communicate with each other, they were found filled with pus, and in each were two worms, male and female.” Dr White expresses his opinion that the worms gained access to the tissues “by boring through the circulatory system while in the embryonic condition.” I think that Dr White deserves great credit for his correct diagnosis of the species, and all the more so because he was evidently not acquainted with Diesing’s original memoir. He expressly speaks of the “scanty descriptions” hitherto given of the worm. As Dr White had accurately determined the species in the presence of an American Scientific Society, it is remarkable that neither Verrill nor Fletcher should have identified the worm.

On the 10th of January, 1871, I received a letter from Prof. W. B. Fletcher, of Indianapolis, Indiana, U.S.A., and in it he announced that he had “found a worm” infesting the hog. The parasite was so abundant in swine that he obtained it in “nine out of ten hogs” which he had examined. Dr Fletcher sent me specimens of the worm for description and identification, when I at once recognised them as examples of Diesing’s Stephanurus dentatus. As Dr Fletcher’s first communication to myself was undated I do not know precisely when he first encountered the worm, but it was in 1870. In that same year Prof. Verrill received specimens of the worm. He says that they were received from Dr J. C. White. Failing to identify the parasites as Stephanuri, Verrill (making no allusion to the ‘Proceedings of the Boston Society’) not unnaturally supposed he had to deal with an entozoon that was new to science. Accordingly he immediately described and figured the worm under the combined title of Sclerostoma pinguicola. If these data are correctly given, the re-discovery of the worm in America was due to Dr J. C. White; its identity with Stephanurus being subsequently acknowledged by Diesing, and afterwards, quite independently, by myself. I gather this partly from Diesing’s ‘Kleine helminthologische Mittheilungen’ (s. 281), published as a supplement to his ‘Revision der Nematoden’ (1860-61). Until quite recently Diesing’s recognition of the identity of White’s parasites with Stephanuri was unknown in America. My conclusions arose from an examination of the actual specimens, whereas Diesing was entirely guided by White’s description. In this connection, moreover, a still more interesting re-discovery remained to be recorded. The original announcement which I made in the ‘British Medical Journal’ for January 14th, 1871, was followed by another in the same periodical for September, 1871. As stated in my second letter and repeated in my notice of Krabbe’s memoir on “Parasites” (‘London Medical Record,’ April 2, 1873), the President of the London Microscopical Society (through Mr Slack, who was at that time the secretary) forwarded to me a box of microscopic slides received by the Society from Australia. The slides displayed parasites of various kinds. Having been requested to identify the parasites I had the good fortune to recognise amongst them characteristic examples of Stephanurus dentatus. Thus was first made known the fact that this singular genus was not confined in its geographical distribution to the two American continents, but that it extended to Australia. The order of the principal “finds” and descriptions may therefore be thus restated. Natterer discovered the worm in Brazil in 1834. Diesing described it in 1839. Dr J. C. White re-discovered and identified the worm in 1858. It was subsequently found by Dr N. Cressy and by Dr Fletcher. These three observers all encountered the parasite in the United States (1858-70). Prof. Verrill re-described the worm as new to science in September, 1870. Diesing confirmed White’s diagnosis in 1860. I identified the worm from Fletcher’s “find” in 1871. Dr Morris supposed he had discovered a new entozoon in Australia in July, 1871. The Australian worms were identified by me as examples of Stephanurus dentatus in October, 1871.

The importance of Stephanurus in relation to porcine epizoöty and the supply of animal food cannot be ignored. As remarked in my communication to ‘Nature,’ it must be quite obvious that so large a parasite, when present in the hog in any considerable numbers, would give rise to serious disease, even if it were not productive of fatal results to the bearer. In one of his numerous communications to myself, Prof. W. B. Fletcher writes as follows:--“It is my opinion that this parasite is the cause, in some way, of the hog cholera, which has created such sad havoc within the past ten years over the pork-producing parts of America. One farmer told me, a few days ago, that within a month his loss alone from this cause was over one hundred head; and sometimes, in one neighbourhood, in a few days’ time, thousands have perished, although this season is not a cholera year, as our farmers say. I advised one farmer to burn or bury the dead animals, but he informed me that he believed that fewer hogs die of the disease after eating the dead animals than those kept from them. Unfortunately, in this State there is no law guarding the spread of disease, neither is there any reward of reputation or gain for pursuing any investigation that would bring pork and beef packers into disrepute. I myself could not get a pig’s kidney or beef’s liver in our city market, because I made investigations in some Texas cattle (being cut up in our market), which damaged their sale a few years ago.” In a third letter Dr Fletcher tells me that greater facilities for examining the carcases of hogs had since been accorded him through the liberality of a Liverpool firm of pork-packers, who had already killed 75,000 hogs during the summer season, i.e. up to the date of the first week in July. In hot weather the slaughtering is conducted in ice-houses. Prof. Fletcher’s views receive confirmation from the statements made by Dr Morris, who speaks of the pigs as dying from some mysterious disease, and thinks that the worms may be the cause of the porcine mortality. Writing to the President of the London Microscopical Society from Sydney (July 12th, 1871), Dr Morris says:--“It is just possible that some pigs may survive the irritation such a swarm of young worms must set up; others, again, may die from peritonitis, hence the sudden deaths amongst the pigs.” I think Dr Morris’ view is perfectly correct, but whether it be so or not, it is (as observed by me in ‘Nature’) interesting to notice the remarkable correspondency of the conclusions arrived at by Drs Fletcher and Morris independently. It will probably not be difficult to ascertain hereafter whether or not the maladies respectively termed “hog cholera” and “mysterious disease” are one and the same disorder, but whatever happens in this respect, it is now quite clear that this parasite, hitherto little regarded, and for many years past persistently overlooked, is extraordinarily prevalent in the United States, and, perhaps, equally so in Australia; it being further evident that its presence in the flesh of swine is capable of producing both disease and death. The statement of the worthy American farmer that the swallowing of infested flesh by pigs does not necessarily involve the pig-eating hog in a bad attack of the so-called “cholera disease” requires to be further tested, and it also remains to be proven whether or not the Stephanurus be capable of passing through all its developmental changes from the egg to the adult form within the body of the bearer without having at some time or other gained access to the outer world. The comparatively large size of the ova, which I find to be about 1/105″, or more than four times the size of Trichina-eggs, is not without significance, but as yet we are entirely unacquainted with the larvæ of Stephanurus. If no intermediary bearers are necessary to its development, we ought not to have to wait long for a complete record of the life-history of Stephanurus dentatus. In conclusion, I will only further remark that since thousands of hogs are infested by this entozoon the subject is worth further investigation. I believe that Prof. Fletcher brought the matter under the notice of the United States National Swine Breeder’s Association, which met at Indianapolis in November, 1872, but with what success I have been unable to learn. The wealthy agricultural societies of Great Britain pay little or no regard to the subject of parasites, although thousands of valuable animals annually perish from the injurious action of entozoa.

Of the remaining nematodes infesting swine I must particularly mention Sclerostoma (Strongylus) dentatum and Strongylus paradoxus, the last named being generally regarded as identical with Dujardin’s S. elongatus. The first of these two parasites infests the small intestines, the male and female worms alike measuring about 1/2″ in length. The females are sometimes a trifle longer. The Sclerostoma dentatum is an abundant parasite, infesting all varieties of swine and also peccaries; but it is apparently incapable of serious injury to the bearer. Schneider selected the male S. dentatum for classificatory purposes. In this worm the arrangement of the rays of the hood is simple, forming a good central type. Dr D. V. Dean, in his excellent report of St Louis Board of Health (1874), speaks of Strongylus dentatus as if it were the same entozoon as Stephanurus. The confusion of nomenclature would have been avoided if Diesing had called the renal worm Stephanurus Nattereri. I hope this title will yet be adopted to prevent future mistakes. The lung-worm (S. paradoxus) is by no means harmless, being a frequent cause of fatal husk in young pigs. It is a viviparous worm, the females acquiring a length of 1-1/2″, whilst the males rarely exceed 3/4″. Under the title Gongylonema pulchrum, Molin has noticed yet another filariform nematode infesting the wild hog; and, lastly, the lamented Russian traveller, Fedschenko, has published a full description of a new species of Gnathostoma (G. hispidum), which infests the coats of the stomach alike of the wild and domestic hog. One of the most interesting parasites of swine is the large acanthocephalous entozoon (Echinorhynchus gigas). It infests the small intestines both of the wild and domesticated hog, and it was also obtained by Natterer from the collared peccary of Tayazou. Common as the great Echinorhynchus is in the United States (and it is scarcely less so on the Continent) I believe that few, if any, of the museums in the United Kingdom of Great Britain contain this large entozoon. It is a curious fact that it does not exist in the Hunterian Collection, where, however, there is displayed a very fine set of acanthocephalous parasites from whales. When in the year 1865 I mounted, with my own hands, 200 preparations of entozoa for the Museum of the Royal College of Surgeons, I had not so much as seen a specimen of this worm. Much scientific interest attaches to this parasite from the fact that Schneider discovered that the embryos of E. gigas take up their residence in the larvæ of the cockchafer (Melolontha vulgaris). He thinks it identical with the Echinorhynchus hominis of Lambl. Leuckart disputes this identity, and compares Lambl’s worm with the Echinorhynchus angustatus of our fresh-water fishes. The E. spirula of certain Brazilian monkeys and of the Barbary ape bears a strong resemblance to the species from the hog. On the strength of Lambl’s case--and it is the only genuine instance of the kind on record--Prof. Leuckart devotes no less than 125 pages of his great work to the consideration of the structure and development of the thorn-headed intestinal worms. This worm demands especial attention. Speaking of the hog’s Echinorhynchus, Prof. Verrill, in his ‘Connecticut Report,’ says that “sometimes the intestine of a hog is found perforated by so many holes that it cannot be used in the manufacture of sausages.” From Mr George Wilkins I learn that the pig-slaughterers of our English metropolis are well acquainted with these perforations, which are sometimes so numerous that the gut looks as if it had been “riddled” with swan-shot. No wonder that diseased hogs, afflicted with these formidable parasites, go about, as Verrill expresses it, “continually squealing and grunting, especially in the morning.” That they are also “cross and morose, and given to biting and snarling at their companions,” is by no means astonishing. “In severe cases,” remarks Verrill, “hogs afflicted with this parasite are weak in the loins, and have the membranes in the corners of the eyes swollen, watery, and lighter colored than usual.” It is some comfort to know that Lambl’s human case is unique, and that so long as people abstain from eating cockchafer larvæ they are not likely to be infested by Echinorhynchus gigas. In the first book of this work I have given my reasons for not regarding Welch’s “encysted Echinorhynchus in man” as a genuine example of this curious genus of entozoa.

The external parasites of swine are not so numerous as might be expected from the habits of their hosts. The most common ectozoon is the hog louse (Hæmatopinus suis). This disgusting little insect is about 1/8″ in length. Almost equally common is the hog mite. Though hitherto considered as a distinct species (Sarcoptes suis, Gurlt), it is regarded by Mégnin as a mere variety of Sarcoptes scabiei. As Gerlach and others have remarked, it is readily transmissible to man. The Sarcoptes squammiferus, of Fürstenburg, is only another name for this variety of S. scabiei. Speaking of this scab-insect Mégnin says:--“This parasite was first encountered by Spinola and Gurlt, and afterwards by Müller.” He then adds:--“A Ceylon wild boar died at the menagerie of the Museum of Paris of a chronic affection of the skin which had transformed its integument into a vast lichen.” Lastly, as regards the protozoal parasites I can only remark that the psorosperms (spoken of as Rainey’s corpuscles or as Miescher’s utricles) are often very abundant in the flesh of otherwise perfectly healthy swine. Having dwelt upon the character of such organisms in the first moiety of this work, I will only remark that the full significance of these singular bodies yet remains to be determined. Rainey’s notion that they represented early stages of cysticercal growth is altogether untenable. According to Behrens, as quoted by Davaine, psorosperms are especially abundant in the flesh of swine which have recovered from the disease called mal rouge. On the subject generally, the writings of Rivolta, Waldenburg, Eimer, and Siedamagrotsky are especially trustworthy. Full references to these and other authorities are given in the synopsis of the 2nd edition of Davaine’s well-known treatise.

BIBLIOGRAPHY (No. 54).--(Anonymous), “On Parasitic Maladies, especially Measles, of the Pig,” from ‘Scottish Farmer and Horticulturist,’ in ‘Edin. Vet. Rev.,’ p. 688, 1861.--Ballard, E., “On Diseased Meat, and what to observe in cases of suspected Poisoning by Meat or Sausages (infected with Entozoa, &c.),” ‘Med. Times and Gaz.,’ Jan., 1864.--Bowditch, H. J., “Raw Pork as an Aliment (without reference to the question of Entozoa.--T. S. C.),” ‘Boston Med. and Surg. Journ.,’ vol. lv, 1857; see also ‘Comments,’ vol. lvi, pp. 23 and 69, 1857.--Cobbold, “On the Discovery of Stephanurus in the United States and in Australia,” in ‘Nature,’ Oct. 21, 1871, p. 508, and in ‘Brit. Med. Journ.,’ Jan. and Sept., 1871; also in the ‘Monthly Micros. Journ.,’ Nov., 1871.--Idem, “Internal Parasites of the Hog,” in ‘Manual,’ chap. xii.--Idem, “On Cystic Entozoa from the Wart-Hog and Red River Hog,” ‘Proc. Zool. Soc.,’ 1861.--Idem, “On Simondsia,” ‘Entoz.,’ p. 79.--Idem, “Note on Worms in the Lungs of a Pig,” in the ‘Field’ for Jan. 9, 1864.--Idem (in relation to Cysticerci or Measles, see Bibl. Nos. 13 and 14, and, for remarks on psorosperms, Bibl. No. 41).--Cressy, N., ‘On the Diseases of Domestic Animals in Connecticut (2nd and 3rd Ann. Reports),’ Hartford, U.S., 1873-74.--Idem, “The demands of Agriculture on Veterinary Science,” in ‘Rep. of the Mass. Board of Agric.,’ 1874.--Idem, ‘Find of Sclerostoma’ (quoted by Verrill).--Crisp, “Note on Hydatid Cysts in the Abdominal Cavity of various Hogs,” ‘Path. Soc. Trans.,’ 1863.--Dardel (see Bibl. No. 14).--Davaine, “Ladrarie chez le porc,” in his ‘Traité,’ 2ème edit., p. 668 (see also the writings of Delpech, Guardia, and especially Reynal, quoted at p. 674).--Dean, D. V., “On Meats and Parasites,” in ‘Seventh Ann. Rep. of Board of Health of the City of St Louis,’ 1874, p. 58 et seq.--Diesing, ‘On Stephanurus’ (quoted in text above).--Dupuy, “Hydatid in a Pig,” from ‘Journ. Théorique et Prat.,’ in the ‘Veterinarian,’ vol. iv, 1831, p. 285.--Fedschenko, ‘Description of new Species of Tetrastemma, Prorhynchus, and Gnathostoma’ (in the Russian language), Moscow, 1872.--Fleming, A., “Measly Pork as Food for Man,” ‘Edin. Vet. Rev.,’ vol. i, p. 485, 1858-59.--Idem, “On the Measle of the Pig, and on the Wholesomeness, as Food for Man, of Measly Pork,” ‘Dubl. Quart. Journ.,’ 1857.--Fletcher (quoted in text above).--Florman (quoted by Rudolphi, ‘Synops.,’ p. 620, 1819; and by Davaine, l. c., p. 723, 1878), in ‘Vetensk. Acad. Nya Handlingar,’ 1810, pp. 179-182.--Gairdner, W. T., “Case of Tapeworm occurring in connection with the Eating of Raw Pork,” ‘Edin. Month. Journ.,’ 1856, and in the ‘Veterinarian,’ vol. xxix, p. 228, 1856.--Gamgee, J., “On Diseased Meat,” ‘Pop. Science Rev.,’ Jan., 1861.--Gordon, “On Tapeworm from Unwholesome Food,” ‘Med. Gaz.,’ 1857.--Gross, S. D., “Note on the frequency of Acephalocysts in Swine at Cincinnati,” in his ‘Elements of Path. Anat.,’ p. 118, 1845.--Gurlt, E. F., ‘Lehrbuch der path. Anat. der Haus-Saügethiere,’ 1831, s. 46, 51, 142, 385.--Heller (see Bibl. No. 13).--Krabbe, ‘Husdyrenes Indvoldsorme’ (l. c., in text; see also review in ‘Lond. Med. Rec.,’ April 2, 1872, p. 206).--Leidy, “Note on Trichina spiralis from the Pig,” from ‘Rep. Acad. Philad.,’ in ‘Ann. Nat. Hist.,’ vol. xix, 1847.--Leuckart (see Bibl. No. 13).--Lewis (Bibl. No. 13).--Martin, J., “Case of Hydatids in the Liver of a Sow,” ‘Trans. Vet. Assoc.,’ pp. 330 and 364, 1842-43.--Mégnin (Bibl. No. 14).--Molin, ‘Una Monog. del Gen. Spiroptera,’ Wien, 1860.--Morris, “Report on Australian Parasites,” ‘Month. Microsc. Journ.,’ Nov., 1871.--Percy, S. R., “On Diseased Meat in relation to Public Health (Prize Essay),” ‘New York Med. Journ.,’ 1866.--Idem, “On the Food of Cities (an Address),” ‘New York,’ 1864.--Perroncito (Bibl. No. 13).--Putz (Bibl. No. 14).--Rainey (Bibl. No. 14).--Rigetti (Bibl. No. 14).--Sawer, A., “Trichina,” in ‘Bost. Med. and Surg. Journ.,’ 1865, p. 16.--Schmidt, Max (see Bibl. No. 51).--Tartivel (Bibl. No. 14).--Thudichum (Bibl. No. 13).--Tommasi (Bibl. No. 13).--Verrill, “On Sclerostoma,” ‘Amer. Journ. Sci. and Arts,’ Sept., 1870.--Idem, “The External and Internal Parasites of Man and Domestic Animals,” from ‘Rep. of the Conn. Board of Agriculture,’ 1870, p. 109.--Walker (see Bibl. No. 20, o).--Wheeler, E. G., “Worms in the Lungs of Swine,” ‘Bost. Med. and Surg. Journ.,’ 1841.--White, J. C., “On Stephanurus,” ‘Proc. Bost. Nat. Hist. Soc.,’ vol. vi, p. 428, 1858.

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XI. (CETACEA)

The parasites of whales are excessively numerous. Unfortunately only a few of the species have been carefully studied, and much confusion necessarily exists as to the number of distinct forms. This statement is especially applicable to the entozoal group, which comprises upwards of a score of species. Probably Van Beneden has examined more of these parasites than any one else, and what little is known respecting them is for the most part due to his investigations. I have myself encountered and described several new species--a circumstance which Prof. Van Beneden appears to have altogether overlooked.

Commencing with the flukes, the first species I notice is Distoma lancea. The late C. M. Diesing’s description of this worm was based upon specimens obtained by Natterer in Brazil. The worms were discovered in the biliary ducts of a male dolphin dissected at Barra do Rio Negro on 29th December, 1833. Natterer calls this cetacean the tacuschi, and in a letter to Diesing names the species Delphinus tacuschi, in order to distinguish it from the D. amazonicus of Spix and Martius. Prof. Flower has shown that Spix and Martius’s D. amazonicus is referable to the inia or Bolivian dolphin (Inia Geoffroyi). The views of Flower, Natterer, and Diesing are thus far in agreement; and the geographical position of Barra shows that Natterer’s dolphin could not be the inia, since, as Blyth long ago remarked, this last named cetacean “inhabits only the remote tributaries of the Amazon and the elevated lakes of Peru.” Several other dolphins from Brazil have been described, one of which Mr Gray named Steno tacuxi. I think that Gray’s cetacean answers to the Delphinus tacuschi of Natterer; but Prof. Flower is of opinion that Gray’s species is an ordinary Delphinus. In this case it may, he thinks, probably be referred either to the D. fluviatilis or to D. pallidus. Whichever view is correct, it is clear that Natterer’s parasite was obtained from a fluviatile cetacean, and not from an oceanic or even an estuary form. In Diesing’s original description it is stated that Natterer found the Distoma lancea “once only,” when numerous examples were secured. To Dr Anderson I stand indebted for a solitary specimen, which he procured from the short-snouted dolphin (Orcella brevirostris, Owen). The obliging superintendent of the Calcutta Museum obtained this Distoma on the 3rd of January, 1873. He removed it from the duodenum, but it had probably escaped from the liver. Be that as it may, I easily recognised the species by the sinuosities of the margin of the body. Dr Anderson’s parasite does not exhibit these marginal irregularities so distinctly and sharply as they are shown in Diesing’s figures. Diesing remarks that the internal organs may be seen through the transparent body. The uterine organs, crowded with ova and of a purple color, are represented by him as branched after the fashion of a raceme. The artist has been misled. The uterine channel is not branched. Dr Anderson’s specimen showed two large oval testes placed one above the other in the middle line, and rather higher up than is usual with those distomes that have the organs presenting this simple form. The ducts were not visible. The yelk-forming glands were particularly well marked, consisting of two laterally-disposed masses, the left gland extending higher up than its fellow. The so-called yelk-cells or capsules were well seen. The oval-shaped eggs were tolerably distinct, yielding a length of 1/750″ from pole to pole, by about 1/900 in transverse diameter. The worm, when unrolled, did not exceed 1/6″ at most, whereas some of Natterer’s specimens measured 1/2″ in length. The neck had lost that rounded character which Diesing called skittle-shaped (kegelförmige). The ventral acetabulum is very nearly twice as large as the oral sucker. Diesing represents the ventral sucker as circular; but in Anderson’s specimen this organ was broadly oval.

The next fluke I have to notice (Distoma Campula) is better known to me. In the twenty-second volume of the ‘Linnean Society’s Transactions’ I first described this new fluke, having secured numerous examples from the peripheral branches of the biliary ducts of a porpoise (Phocæna communis). The apparently healthy cetacean was shot by Mr Jardine Murray in the Firth of Forth, in April, 1855. I mention its condition because the bile-ducts were found to be diseased in a way similar to that ordinarily observed in cases of fluke-rot affecting sheep, cattle, and other animals. In my MS. note-book I remarked: “The liver-ducts were in several places thickened and knotted near the surface of the organ. On opening these they were found to be loaded with small distomata.” It was added that, so long as the flukes were alive, they displayed under the microscope a “double and peculiar intestinal tube,” the skin being clothed with spines arranged throughout with perfect regularity. When the superficial ducts were dissected out they presented a distinctly beaded appearance, the enlargements of the lumen being occupied by flukes closely packed together. At least twenty were found in one spot. One of these enlarged ducts is figured in my recent paper to the Linnean Society (quoted below). The most striking feature connected with the structure of Distoma Campula is the twisted condition of the digestive canals. They present a zigzag appearance, the lateral folds being so sharp that they seem to constitute, as it were, a transition between the ordinary simple intestinal tubes of a true Distoma and the branched tubes seen in Fasciola. This led me originally to place the worms in a distinct genus (Campula). Perhaps there were no sufficient grounds for this generic separation; but in all Dr Anderson’s specimens obtained from the liver-ducts of the Gangetic dolphin more or less decomposition of the contents of the intestinal tubes had occurred, consequently the angular appearance of the folds is entirely lost. From the other characters presented by the worms I believe that these flukes from the Ganges are specifically identical with those originally obtained from the porpoise of the Firth of Forth. For reasons elsewhere stated at full length I have merged my genus Campula into that of Distoma. Thus, Campula oblonga is a synonym only. I cannot here treat of the morphology of trematode organisation as it deserves; but in relation to the question of transition-forms I may remark in passing that an extreme degree of intestinal folding seems as if it must result in branching. This, I think, would happen should any departure from the central distome type be rendered necessary by the exigences of the creature. At all events, the spirally-twisted and branched digestive organs constitute different ways in which nature attains one and the same end. I may add that this coiled condition of the tubes in D. Campula is by no means unique, since I have seen it in other trematode forms, as, for example, in my D. compactum from the Indian ichneumon. Dr Anderson’s specimens of D. Campula furnish a good general view of the reproductive organs. They show that the single, relatively narrow, and unbranched uterine canal is of great length, and coiled upon itself in a very tortuous manner. In this way the duct passes from side to side, crossing the central line of the body at least a dozen times, whilst every fold is likewise bent upon itself to such an extent as to increase its length to at least four times that of the animal. In short, the uterine folds may be described as passing from side to side, each separate coil being twisted upon itself so as to form secondary coils. In the fluke here drawn I have accurately represented every winding of the duct, from its vaginal outlet above to its termination, where it is joined by the ovarian and vitelligene ducts in the ordinary way. Only the merest traces of these smaller channels were visible; but the two oval testes were well defined, occupying a position somewhat lower down than usual. There was a third organ, apparently the ovary. This was less well defined, and situated higher up in the middle line. The vitelligene glands occupied the usual position. The terminal cells or capsules with their efferent ducts were well seen in several specimens. The water-vascular system was constantly visible, or at least that part of the main channel which expands into a large vesicle immediately above the central point of the tail. At this part several of the specimens ruptured. In all of the worms the lower end exhibited a sort of tail, resulting from post-mortem changes. None of the Edinburgh specimens of Campula displayed either the slightest trace of this projection or of the water-vessel connected with it. The uterine duct was filled with eggs. Approximately, the ova gave a measurement of 1/1000″ from pole to pole by 1/2100″ in breadth. Although in Anderson’s specimens the integumentary spines had fallen off, they are still attached in my original specimens from Edinburgh. The spines average 1/500″ in length. With their shafts directed downwards they separately presented the form of a long cone, the base of which was only 1/1000″ broad. After describing the above-mentioned trematodes I received a letter from Dr Anderson, in which he enclosed a sketch of a parasite taken from the small intestine of another Platanista. The illustration evidently represented a new species of cetacean fluke which I called Distoma Andersoni, with the following diagnosis:--“Body oblong, smooth externally, uniform in thickness, six times as long as broad; head with lateral projections; ventral sucker large and prominent; neck much constricted; tail evenly rounded off, blunt. Length 1/8″, breadth about 1/50″.” This worm, which was discovered by Anderson, in March, 1873, is figured in my memoir communicated to the Linnean Society. Only one parasite was found. The figure in question shows that in this species the testes are globular and placed high up in the middle line of the body. A small lobed gland immediately above the testes is probably the ovary. The vitelligene glands are largely developed. In the year 1858 Van Beneden described a large fluke from the pike-whale (Balænoptera rostrata). The specimens were from Eschricht’s collection and had been removed from the liver. As some of the examples measured no less than 80 millimètres, Van Beneden described them as “the largest known distomes.” This is probably correct, but the great human fluke (D. crassum) reaches 2-1/2″, and the giraffe’s fluke (Fasciola gigantea) 3 inches in length. The curator of the Australian Museum, at Sydney, Mr Gerard Krefft, mentions a Distoma which himself and Mr George Masters obtained from Delphinus Forsteri. Not improbably it represents a new species. Of the single-suckered flukes, Creplin in 1825 obtained Monostoma plicatum from the intestines and œsophagus of a northern whale. This cetacean was obtained on the coast of the island of Rugen, in the Baltic. It has been variously spoken of as Balæna borealis or B. rostrata, but by Van Beneden this cetacean is called Balænoptera musculus. The flukes exceeded 1/4″ in length. Another species of monostome (M. delphini) was vaguely indicated by Blainville as occupying the cutaneous follicles of Delphinus Dalei, which cetacean is a synonym of Micropteron sowerbiensis. The same worm is supposed by Van Beneden to infest the bottle-head (Hyperoodon butzkopf), and perhaps it was the same or a similar worm which Poelman found in the flesh of Lagenorhynchus Eschrichti. By naturalists imperfectly acquainted with helminths, the monostomes are apt to be confounded with Cysticerci; nevertheless, these widely different types may coexist in the same host. The presence of larval cestodes has been indicated in various whales. Thus, F. Cuvier and Van Beneden state that Surgeon-Major Carnot, in 1822, found an enormous quantity of small hydatids in the nasal sinuses of a porpoise (Phocæna compressicaudata). These are supposed to be Cysticerci. In like manner Mr F. D. Bennett, in 1837, obtained numerous capsuled Cysticerci from the skin and blubber of Catodon (Physeter) macrocephalus. It is unfortunate that so few of the cetacean helminths find their way into the hands of persons competent to decide upon their true character.

Mr Bennett’s “find” was originally stated to have been made in Balæna mysticetus, but Van Beneden refers it to the northern sperm-whale or blunt-headed cachalot. The naturalist Bosc noticed a larval cestode found in the fatty tissues surrounding the reproductive organs of Delphinus delphis. He called it an hydatid (Hydatis), and Rudolphi placed it with the Cysticerci (C. delphini). According to Van Beneden the parasite in question is probably a sexually-immature example of the Phyllobothrium delphini described by his son. Edouard Van Beneden found this scolex in great abundance in a dolphin (Delphinus delphis), which he dissected at Concarneau in 1868. The sexually-mature state of this worm is, as the Belgian savans remark, to be looked for in some one or other of the larger sharks. The Phyllobothrium has also been found in the black fish, tursio, or high-finned cachalot (Physeter tursio). M. Gerrard Krefft has described a cestode from the stomach of a dolphin (Delphinus Forsteri), which he terms Tænia Forsteri. The strobile only measured 2-1/2″ in length. It is just possible that the worm may be identical with the species found by Schott. Unfortunately M. Krefft did not find any ova, and his figures do not indicate the position of the reproductive pores, if, indeed, they were present. In this place, therefore, it is fitting to remark that, under the name of Tetrabothrium triangulare, Diesing has furnished the diagnosis of a small cestode found by Schott in Delphinus rostratus off the coast of Portugal. The strobile measured only two or three inches in length, and showed a uniserial disposition of the reproductive pores. Remarking on this species Van Beneden has stated that this is the only sexually-mature tapeworm hitherto encountered in the intestines of the cetacea. This observation, made in 1870, is somewhat unfortunate, because I had already, in the year 1855, described a very large and mature form of cestode (Diphyllobothrium stemmacephalum) from the common porpoise (Delphinus phocæna). As stated by me to the Linnean Society in December, 1857, the small intestine of this porpoise was completely choked for the space of eight or nine feet by fine tapeworms so closely packed together that the gut presented the appearance of a solid cylinder. The same porpoise yielded the flukes already described (D. Campula). As afterwards remarked in my treatise on the ‘Entozoa’ (1864), four of the tapeworms measured, respectively, from 7′ to 10′ in length, the fifth example being relatively small (18″ only). For a full description of the worm I must refer either to the Linnean ‘Transactions’ or to my introductory volume whence the figures here given are taken. Five of the finest examples of this remarkable cestode have been added to the small collection of entozoa which I prepared for the Museum of the Middlesex Hospital Medical College. The head of this large cestode is excessively minute. The same cetacean host not only yielded these new cestodes and flukes, but also great numbers of the well-known strongyloid lung-worms, called Prosthecosacter inflexus and P. convolutus. Another species (P. minor or Pharurus minor) also infests the porpoise, and a fourth (P. alatus) the narwhal. As I have elsewhere observed (‘Entozoa,’ p. 91), the three first mentioned forms are readily distinguishable from each other by their relative size and length, and also more especially by the form of the tail. The females of P. inflexus attain a length of nine inches, and those of P. convolutus may be upwards of 1-1/2″ in length, whilst those of P. minor do not exceed an inch. The species described by Leuckart, from Monodon monoceros, is only half an inch long. All the forms infesting the porpoise were met with by Professor Quekett, and one of them has been carefully anatomised by Professor Busk. Probably several other species will be discovered when the lungs and cranial sinuses of the larger cetacea are carefully examined for this purpose. The form (P. convolutus) here represented is the least known of the three infesting the porpoise. This species has been dissected by Kuhn and Eschricht, whilst the other species have not only been examined by these authors, but also by Raspail, Dujardin, Von Siebold, Van Beneden, Leidy, and several other helminthologists. Some of Professor Busk’s examples of the male worm (P. convolutus) were fully fifteen lines long, yet, from the condition of the internal reproductive organs, he was led to believe that they were not quite fully grown. I cannot here repeat the anatomical details given in my former work, but I may add that all the species of this genus reproduce viviparously. If the worms are examined in the fresh state the young may occasionally be seen escaping by the vagina. Professor Van Beneden noticed this phenomenon in Prosthecosacter inflexus, and the same thing was observed by Busk in P. convolutus. In the instance here drawn (Fig. 71) one of the embryos is in the act of emerging, its caudal extremity being still lodged within the vulva of the parent. In the fresh worm one may also see, under the magnifying glass, numerous young worms coiled together within the oviduct; the last-named organ widening out into a capacious sac at a little distance above the end of the tail. The embryos measure about 1/300″ by 1/5000″ in breadth. Higher up, within the uterine and ovarian ducts, the ova may be seen in all stages of development, according to the particular region of the tube under examination. In their full-grown condition the eggs have a longitudinal diameter of 1/1100″ by a transverse measurement of about 1/1700″.

As regards the development and migrations of the young worms, it is highly probable that the embryos enter the bodies of various fishes before they have acquired sexual maturity. Thence they will be passively transferred to the stomachs of cetacea, whence they bore their way through the tissues to the bronchi and pulmonary vessels. Though usually found in these situations they also infest the cranial sinuses. Prosthecosacter minor is frequently lodged within the cavity of the tympanum. Professor Quekett and myself, working independently, found examples of P. inflexus occupying the chambers of the heart. Under the name of Filaria inflexicaudata, Prof. Von Siebold has described yet another pulmonary nematode from the porpoise. It occupied cysts in the lung. Like the strongyloids above mentioned, the females are viviparous, but the males are destitute of any caudal hood. In the whale (Balænoptera) killed off the isle of Rugen, and already alluded to, M. Rosenthal obtained a large number of Filariæ (F. crassicauda, Creplin). To employ Dujardin’s words the worms were situated “dans les corps caverneux du pénis d’une Balæna rostrata.” The males and females measured respectively 6-1/2 and 13 inches in length. Several forms of ascarides are known to infest cetaceans. The species called Ascaris simplex by Rudolphi was originally procured from the œsophagus and stomach of the dolphin of the Ganges and afterwards by Albers from the common porpoise. According to Diesing the worms obtained by Dussumier from a dolphin, taken off the Maldive Islands, must be referred to the same species, but Van Beneden maintains that Dussumier’s “find” refers to a distinct species, which he calls Ascaris Dussumierii. To this view I cannot see any objection, but I think that Van Beneden’s retention of Lebeck’s Ascaris delphini as distinct from A. simplex is untenable. Speaking of examples of this entozoon received from Calcutta, I have remarked in the ‘Zoological Society’s Proceedings’ that Dr John Anderson’s collection of parasites showed four specimens of this species. The worms had been obtained from the intestines of Platanista gangetica. Singular to say, all the examples were of the female sex, the two largest measuring about 1-3/8″ from head to tail. The smaller worms did not exceed one inch in length. In connection with these specimens (all of which were carefully examined by me on the 28th of September, 1875) I have only to add that they presented the peculiarly flexed state of the chylous intestine described by Dujardin. As that helminthologist had accurately surmised, the Ascaris delphini of Rudolphi must be regarded as identical with this species. It is impossible to say how many distinct species of cetacean lumbricoid worms exist. Messrs Krefft and Masters found a species of Ascaris infesting a Delphinus Forsteri taken off Sidney, New South Wales. Creplin also, in 1851, described a species (A. angulivalvis) from the intestines of Balæna rostrata. The males are less than three inches long, the females measuring 3-1/2″. The late C. M. Diesing received from Prof. Steenstrup a notice of some nematodes taken from a narwhal (Monodon monoceros), which appeared to the Vienna authority to be scarcely different from Creplin’s worm. Under the title Conocephalus typicus Diesing has both figured and described a remarkable nematode, two inches in length, which possesses the power of retracting its conical, or, rather, mushroom-shaped head within the body, somewhat after the manner of certain Echinorhynchi. His description is based upon museum specimens that were obtained from the stomach of a dolphin (probably Delphinus delphis) captured in the Atlantic Ocean. In addition to the above nematodes some few others remain to be mentioned. Thus, the Peritrachelius insignis of Diesing was obtained by Natterer from the stomach of Delphinus amazonicus (Spix and Martius). The largest males measured 3-1/2″ and the females 5-1/2″.

Another singular parasite, named by its discoverer, Roussel de Vauzème, Odontobius ceti, was found by him in the mucus covering the bristles (fanons) of Balæna australis. The separate worms measured about 1/5″ in length only, but they occurred in very great numbers. Lastly, Van Beneden points to certain filiform worms found by Pallas in the cavity of the ear of Beluga leucas as probably representing another distinct species of nematode, which he designates Strongylus Pallasii. I suspect, however, they will only have been fine specimens of Prosthecosacter minor. Be that as it may, it is as well to be reminded that Albers and Mehlis, and also Klein, Camper, and Rosenthal, found P. minor within the tympanic cavity of the common porpoise. When looking into the Museum stores of the Royal College of Surgeons, I found many choice examples of the genus Prosthecosacter. Some few were evidently Hunterian, but others had been separately contributed by Professors Owen and Quekett.

The acanthocephalous entozoa are well represented in whales. One of the commonest species is Echinorhynchus porrigens, of which I possess specimens given me by Prof. Goodsir, who procured them from a Balænoptera rostrata, captured in the Firth of Forth. The Hunterian Collection contains examples of this worm, recorded as having been obtained from Balæna mysticetus; and also several Echinorhynchi from the pike-whale. Professor Owen regards these last-named entozoa as distinct (E. balanocephalus, Owen). Probably Hunter’s whale-worms, which resembled E. filicollis of the eider duck, and which Van Beneden has characterised as representing a distinct species (E. mysticeti), were examples of E. porrigens. The specimens set up by me for the Museum of the Royal College of Surgeons were all of Hunterian origin. The whole subject of cetacean Echinorhynchi requires revision, and would well repay special investigation. The small, oval-shaped entozoa found by Murie in a whale which Van Beneden refers to Balænoptera musculus were probably examples of a distinct species of this genus (E. Muriei). The Vienna helminthologist has described a small species (E. turbinella) obtained by Hyrtl from Hyperoodon butzkopf. The male worms measured 1/2″ in length. Another small species (F. pellucidus) was discovered by Leuckart in the intestines of Delphinus delphis, the males measuring less than 1/4″, and the females about 1/2 an inch. Lastly, under the name of Echinorhynchus brevicollis, Van Beneden has indicated another species found by Malm in the intestines of a curious whale (Balænoptera Sibbaldii) captured alive off the coast of Sweden. The Louvain savant refers to the “take” of another example of this rare whale in the Firth of Forth about the same period. A good many whales have been captured of late years off our English and Scottish coasts, but, unfortunately, very little effort has been made to collect the numerous entozoa which they undoubtedly will have contained.

The external parasites and fellow-boarders or messmates of Cetacea are almost as numerous as helminths. In this work, however, little account can be taken of them. Every naturalist is familiar with the common Cyamus balænarum, and voyagers tell us that the whales are sometimes so densely covered by these lice that they impart to the skin a white color, and so enable the fishermen to see their victims at a great distance. The Cyami and Caprellæ are closely allied forms of læmodipodous crustaceans. Professor Lütken, of Copenhagen, has enumerated about a dozen distinct species of Cyami which are parasitic upon whales. Some of the Pycnogonidæ are said to attach themselves to whales. In their young state they are known to be parasitic upon polyps. I obtained specimens of these in 1856. The barnacles found on whales are genuine messmates; when once they have attached themselves to the skin, they remain permanently fixed. Like the Cyami or true whale-lice, these parasitic cirrhipeds are so numerous that almost every cetacean host may be said to carry its own species of louse and its own species of barnacle. The classification of these creatures is an admitted difficulty, even amongst skilled crustaceologists. The genera of cirrhipeds that are parasitic upon whales chiefly belong to the genera Coronula, Diadema, Tubicinella, and Conchoderma, but in addition to these, many lernæans of the genera Penella and Lerneonema are found on whales, and also, according to Van Beneden, at least one species of Acarus. This mite (Acaridina balænarum, Van Beneden) is found on Balæna australis. Here I must stop. The limits of this work preclude my attempting a more extended notice or enumeration of the crustacean and arachnidan parasites.

Notwithstanding the known differences existing between the phytophagous manatee-dugong group and the true whales, the parasites of this remarkable order of mammals (Sirenia) will be most conveniently noticed in this place. Not much is known respecting them. A single species of Amphistome (A. fabaceum) of the usual size has been described and figured by Diesing from the cæcum and large intestine of Natterer’s manatee (Manatus exunguis), the same mammal yielding a rather peculiar nematode, Heterocheilus tunicatus. This worm possesses a complicated set of cephalic lobes and oral papillæ, which at first induced Diesing to call the genus Lobocephalus. These structures have been fully described and figured in Diesing’s account of the anatomy of the worm in the ‘Annals of the Vienna Museum.’ The males measure 1-1/4″ and the females up to 1-1/2″ in length. From the stomach of an Indian dugong (Halicore) Rüppell and several other naturalists obtained lumbricoid worms (Ascaris halicoris, Owen), the males of which measured 2-1/4″ and the females from four to five inches in length. Rüppell’s specimens were from the Red Sea and Owen’s from Penang. From the now extinct Rhytina Stelleri similar worms were obtained by Steller, who called them Lumbrici caudidi. Following Brandt’s nomenclature the species has since been recognised as Ascaris rhytinæ. The worms measured half a foot in length, and occupied the stomach and duodenum. They were obtained by Steller in July, 1742, the last of the Rhytinas having been seen in 1768.

BIBLIOGRAPHY (No. 55).--Baird, “Entozoa of Cete,” ‘Brit. Mus. Catalogue,’ Index, p. 120, 1853:--Idem, “Ascaris halicoris,” in ‘Ann. Nat. Hist.,’ 1860, p. 329; see also “Description of a rare Entozoon from the Stomach of the Dugong,” ‘Proc. Zool. Soc.,’ 1859.--Beneden, P. J. van, “Les Cétacés, leurs commensaux et leurs parasites,” ‘Bullet. de l’Acad. Royale de Belgique,’ p. 348, 1870.--Idem, ‘Animal Parasites,’ 1876.--Beneden, E. van, in ‘Comptes Rendus,’ 1868.--Bennett, D., in ‘Proc. Zool. Soc.,’ 1837, p. 30.--Brandt, “Asc. dugonis and A. rhytinæ,” in ‘Bull. P.-Math. de l’Acad. Imp. des Sci. de St Peters,’ tom. v, p. 192.--Cobbold, “Trematode Parasites from the Dolphins of the Ganges, Platanista gangetica and Orcella brevirostris,” ‘Linn. Soc. Journ.,’ Zool. Div., vol. xiii, p. 35, 1876.--Idem, “Entozoa of Delphinus phocæna,” ‘Linn. Soc. Trans.,’ vol. xvii, p. 167, 1858.--Idem, “Descript. of Asc. Andersoni,” in ‘Notes on Entozoa,’ part iv, in ‘Proc. Zool. Soc.,’ March, 1876, p. 296.--Idem, ‘Catalogue of the Specimens of Entozoa in the Museum of the Royal College of Surgeons (Preps. Nos. 39-43 and 98-101),’ 1866; see also Owen, for an account of the Hunterian specimens of Echinorhynchi.--Creplin, F. C. H., “Note on a Filaria and a Monostoma from a Whale (Balæna rostrata),” from ‘Nova Acta Acad. N. C.,’ xiv, in ‘Zool. Journ.,’ 1832-34, vol. v, p. 381; and in ‘Ersch. and Grube’s Encyclop.,’ 1846, s. 172.--Idem, “On Asc. angulivalvis,” in ‘Wiegmann’s Archiv,’ 1851, s. 158.--Diesing, “On Heterocheilus and Amphist. fabaceum,” in ‘Neue Gattungen von Binnenwürmen (u. s. w.),’ ‘Annalen des Wiener Museums,’ 1839.--Idem, “Descr. of Conocephalus,” in ‘Revision der Nematoden’ (1860), from ‘Sitzungsb. d. k. Akad. d. w. math.-naturw.,’ 1861, s. 669.--Dujardin, ‘On Odontobius,’ l. c., p. 292.--Idem, ‘Ech. porrigens,’ p. 504.--Idem, ‘Fil. crassicauda,’ p. 50.--Idem, ‘Stenurus,’ p. 266.--Idem, ‘Asc. simplex,’ p. 220.--Krefft, “Parasites of Forster’s Dolphin,” in his ‘Australian Entozoa,’ from ‘Trans. Etom. Soc. of New South Wales,’ Sydney, 1871.--Lebeck, “Asc. delphini” (quoted by Rudolphi), Synops., p. 296, from ‘Neue Schriften der Berl. Gesellsch. Naturf. Freunde,’ Bd. iii, s. 282.--Leuckart, R., “On Pharurus,” in ‘Wiegmann’s Archiv,’ 1848, s. 26.--Murie, in ‘Proc. Zool. Soc.,’ 1865, p. 213.--Owen, “Asc. halicoris,” ‘Zool. Soc. Proc.,’ 1838, and in art. “Entoz.,” ‘Todd’s Cyclop.’--Idem, “On Echinorhynchi,” in his ‘Catal. of the Contents of the Roy. Coll. Surg. Museum,’ part iv, fasc. i, p. 44; and for the “External Parasites of Whales,” ibid., p. 74, 1830.--Quekett, J., “On the Anatomy of four species of Entozoa,” abstract from ‘Proc. of Micros. Soc.,’ in ‘Ann. of Nat. Hist.,’ vol. viii, 1842; also in ‘Micros. Journ. and Struct. Rec.,’ p. 125, and in the original series of ‘Trans. of the Micros. Soc. of Lond.,’ vol. i, p. 44, 1844.--Idem, in ‘Baird’s Brit. Mus. Catal. of Entoz.,’ p. 3, 1853.--Roussel de Vauzème, “On Odontobius,” ‘Ann. des Sci. Nat.,’ 1834, p. 326, and in ‘Isis,’ 1836.--Rüppell, “Entozoa Dugonis,” in ‘Abhandl. der Senkenbergschen Museums,’ i, s. 106.--Siebold, Von, “On Filaria inflexicaudata,” in ‘Wiegmann’s Archiv,’ 1842, s. 347.

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XII. (MARSUPIALIA)

The well-known fact that, in respect of their habits, the pouched mammals epitomise, as it were, the non-marsupial quadrupeds, would naturally lead us to look for a repetition of corresponding type-forms of entozoa as guests within their bodies. Speaking generally, the inference is correct; but very few of the entozoa hitherto found in marsupials correspond, as species, with those infesting man and non-pouched mammalia. A noteworthy exception occurs in the case of the common liver-fluke, which is abundant in the great kangaroo (Macropus major). This fact was well known to Bremser and all the older helminthologists, and it has since been confirmed by numerous observers resident in Australia. The late Dr Rowe, an acute observer and successful stock-breeder, who wrote chiefly in connection with the sanitary bearings of parasitism, remarked that “the native animals of Australia are much infested with internal parasites. Some of those now found in the kangaroo and the smaller marsupials may have been derived from our domestic animals; but tapeworms and other internal parasites have been met with in animals occupying regions wholly unsettled.” Precisely so. That is just what we should expect. The Australian indigenous mammals have their own entozoa as a matter of course, and, in addition, they have contracted a few species from the domestic animals introduced into the country. On the whole, however, it cannot be said that the parasites of marsupials are of much practical consequence to agriculturists, since, with the exception of flukes, and probably hydatids, the Australian marsupials do not appear to harbor any entozoa that are likely to prove injurious to man and his domestic companions. The amount of fluke-germ distribution by kangaroos must be infinitesimal as compared with that proceeding from sheep and other kinds of “stock;” therefore on the score of parasitism alone it is not desirable to hasten the slaughter of kangaroos. From the scientific standpoint, it is to be regretted that the naturalists of New South Wales and other colonies have done so little towards defining the various species of marsupial entozoa. Mr Krefft, in his interesting brochure on Australian entozoa, describes a few tapeworms, and also points to several round worms which may be new to science, but with the exception of the common fluke no trematode appears to have been encountered by himself or Mr Masters in the various marsupials which they examined in the neighbourhood of Sydney and Queensland. Dr Bancroft, of Brisbane, has placed in my hands a small collection of entozoa, several of which have been obtained from marsupials, but their identification remains partly in abeyance.

Besides the liver-fluke, the only marsupial trematodes at present fairly described appear to be Hemistoma alatum, and two species of Rhopalophorus (R. coronatus and R. horridus). All of these were obtained by Natterer from the opossums of tropical America. One of these flukes was described at some length by Rudolphi, who called the species Distoma coronatum, and gave its length as varying from two to four lines. Diesing, in one of his best illustrated monographs, has shown that the opossums in question are infested by two distinct species of fluke, which must be generically separated from the distomes. These singular Rhopalophori are furnished with a pair of armed retractile proboscides (Bohrüsseln), which must form powerful organs of anchorage. The worms are found attached to the walls of the stomach and small intestines.

The tapeworms of marsupials are more numerous than flukes. Thus, we have Rudolphi’s Tænia festiva, eight to ten inches in length, occupying the gall-bladder and hepatic duct of Macropus giganteus. Dr Bancroft’s collection contains two almost perfect examples of a tapeworm which he procured from a small streaked kangaroo (Halmaturus Derbyanus). These I have identified as T. festiva. In this worm the reproductive papillæ, not hitherto observed, are biserially arranged. Fragments of a tapeworm (T. didelphidis) are preserved in the Vienna Museum, taken from the intestines of the American Didelphis murina. From different species of wallaby (Halmaturus) Mr Gerard Krefft has given more or less complete descriptions of two tapeworms (Tænia fimbriata, and T. Mastersii), and a probable Bothriocephalus (B. marginatus). I am not in a position to pronounce upon the distinctness of these Australian Tæniæ; but I may observe that Krefft’s T. fimbriata comes very near to another species which Dr Bancroft has given me. The Brisbane savant obtained the worm from a koala (Phascolarctos cinereus). Provisionally I call this species Tænia geophiloides, in allusion to its general resemblance to a long millipede. The single, perfect strobile, with the head attached, measures thirteen inches in length. Prof. Leidy has furnished a description of another tapeworm (T. bipapillosa) from a wombat (Phascolomys), and Mr Krefft has described yet another species obtained from the common vulpine opossum (Phalangista vulpina). The single example in Krefft’s possession measures four inches in length. He has named it Tænia phalangistæ. Some of the American opossums (Didelphys brachyura, and D. quica) have been found to harbor a species of ligula (L. reptans, Diesing) in the sexually-immature state. Lastly, I find in Bancroft’s collection several tapeworms obtained from that small and interesting monotreme marsupial commonly known as the Australian hedgehog, echidna, or porcupine ant-eater of the colonists (Tachyglossus setosus). The strobiles, which are nearly perfect, average three inches in length, and are made of very narrow and closely-set proglottides. This species is evidently new to science, and as such I propose to call it Tænia phoptica, in allusion to its thick-set appearance and its consequent burdensome character to the bearer. The largest proglottides measure fully 3/8″ in width. There can be little doubt that the presence of any considerable number of such comparatively large tapeworms must seriously incommode, if they do not actually prove fatal to their unfortunate hosts.

So far as regards mere variety of species, the nematode fauna of marsupials is probably far in excess of that of the trematodes and cestodes. I cannot therefore do much more than enumerate the species. The Hunterian Museum of the Royal College of Surgeons contains the original “worms found alive within the capsular ligaments of the knee-joint of a kangaroo,” which have been indicated as Filariæ macropodis gigantei. It would, in my opinion, be far better to call the worm, after its discoverer, Webster’s filaria (F. Websteri). Dr Bancroft has likewise encountered this same parasite in the great kangaroo. From the abdominal cavity of a wallaby Leidy has also obtained a filaria (F. spelæa). The American opossums (Didelphys) are much infested by Ascaris tentaculata, which is found in the cæcum, and many of them also harbor a small whipworm (Trichocephalus minutus). Another tolerably abundant nematode (Physaloptera turgida) was obtained by Natterer from the stomach of Didelphys azaræ, D. myosurus, and D. cancrivora. The only other nematode mentioned in Diesing’s ‘Systema’ is Aspidocephalus scoleciformis. This is found in D. murina, and D. domestica. From the opossum of the United States (D. virginiana) Prof. Leidy has also obtained Asc. tentaculata, Trichocephalus minutus, and Physaloptera (Spiroptera) turgida. According to Molin there are grounds for separating some of these stomach-worms into distinct species. Thus, he has recognised the examples found by Natterer in Didelphys myosurus as belonging to the genus Histiocephalus, as emended by himself. If the separation be allowed, then we must add to the list Molin’s Histiocephalus subulatus. From Bancroft’s collection I am certainly in possession of two distinct kinds of nematode taken from the stomach of Halmaturus Derbyensis. I have also two species of nematode from Macropus giganteus. Their identification, however, is a matter for future consideration. Lastly, as regards the acanthocephalous parasites, only one species appears to have been described. This worm (Echinorhynchus microcephalus) was obtained by Olfers in Brazil, from the intestines of Didelphus philander. It also occurs in D. virginiana. Being a tolerably large species, that is to say 3″ in length, it seems surprising that it has not been found in the American opossums generally.

BIBLIOGRAPHY (No. 56).--Cobbold (see Rowe). Diesing, ‘Syst.,’ l. c., p. 519; also monogr. ‘Binnenwürmen’ (l. c., Bibl. No. 55).--Krefft, G., ‘Australian Entozoa’ (l. c., Bibl. No. 55).--Leidy, ‘Proc. Philad. Acad.,’ 1856.--Idem, “Tapeworm from the Wombat,” ibid., 1875, p. 6.--Molin, “Una monogr. del genere Physaloptera,” p. 10, “Una monogr. del gen. Dispharagus,” and “Una monogr. del gen. Histiocephalus,” p. 37, aus dem xxxix Bd., d. ‘Sitz. d. m.-nat. Cl. d. k. Akad. der Wissensch.,’ s. 479-507 und s. 637-672, 1860.--Rowe, J., “Parasitism in Australia” (in which the author sought to benefit stock-owners by utilising, prophylactically, my published opinions), repr. from the ‘Melbourne Leader’ in the ‘Veterinarian,’ May, 1874.--Rudolphi (in ref. to Dist. coronatum), ‘Synops.,’ p. 116 and 686.--Webster (respecting his “Filaria,” see), ‘Catalogue of the Hunterian Collection of Entozoa,’ p. 7, prep. 49, 1866; also the old ‘Catal. of the Museum Roy. Coll. Surg.’ (by Owen), part iv, fasc. i, p. 37, No. 170; also Diesing’s ‘System,’ p. 280, and Froriep’s ‘Notizen,’ Bd. xlii, s. 328.

SECTION II.

To give an air of completeness to this treatise, I shall devote the few pages remaining at my disposal to a brief summary of the general facts of parasitism as witnessed in birds, reptiles, fishes, and evertebrated animals. For details I must refer to the separate original works and memoirs quoted in the appended bibliographies.

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I. (AVES)

A prodigious number of entozoa are known to infest birds. So far from birds being less victimised than mammals, the contrary is the case. Every now and then avian epizoötics, due to parasites, sweep off hundreds of these attractive hosts, and in some cases even nestlings are not secure from entozoal invasion. It might be supposed that predacious birds would be more liable to invasion than the graminivorous species. Such is not the case. The eagles, hawks, vultures, and owls certainly harbor a great variety of helminths, but as much may be said of the grain-feeding game birds, and still more of the water birds. Pheasants and land-fowl, grouse and partridges, are largely infested; whilst, of water-fowl, herons and plovers, rails and snipe, ducks and geese, cormorants and divers, gulls and awks, play the rôle of host to a practically infinite variety of parasitic guests. The presence of the worm-guests does not imply any previously diseased condition of the host. Shoot any water bird, say an oyster catcher (Hæmatopus), or, still better, a grebe (Podiceps), and then carefully examine its intestinal contents. You will probably find in its interior flukes and round worms, tapeworms and Echinorhynchi. Capture and examine a frog or a salamander. The result is the same, except that the cestodes would probably be absent. As for fishes, if entozoa be a proof of cachexia, then it follows that the normal condition of all piscine hosts is a diseased state. Examine any tolerably well-grown salmon, trout, pike, perch, roach, chub, carp, or barbel, and probably any one of them will contain at least three different kinds of parasites, each of which will be present in more or less considerable numbers. From what is stated above it would be obviously futile to attempt even an enumeration of the species of avian entozoa--a remark which applies almost equally to the other groups of hosts that remain for consideration. Confining our attention to a few of the more noteworthy facts, I may observe that we have no very trustworthy data respecting the power for mischief possessed by flukes. From what we know of their destructiveness in man and certain other mammals, it would be hazardous to pronounce them harmless. Scientifically, they furnish particulars of great interest. One of the most striking facts of recent study relates to Zeller’s discovery that the little cercariæ (C. exfoliata) which are contained in a peculiar sporocyst (Leucochloridium paradoxum), infesting the tentacles of a snail (Succinea amphibia), are in reality larval forms of a fluke (Distoma macrostomum) which resides in the intestinal canal of warblers (Sylviadæ). By experiment Dr Zeller reared the Distoma in question in the intestines of whitethroats (Curruca garrula), in blackcaps (C. atricapilla), and in wagtails (Motacilla). Six days after transference the Cercariæ acquired sexual maturity. The odd thing is, that as the sporocystic Leucochloridia resemble insect larvæ, they are attacked and swallowed by the birds under delusion. It is a curious example of mimetism in favour of the fluke’s welfare. To this and other equally brilliant scientific results helminthologists were gradually led up by the earlier researches of Steenstrup and Van Beneden. As remarked in my ‘Entozoa,’ ever since Steenstrup’s discovery of the fact that Cercariæ found in the bodies of water-snails were larval flukes, a peculiar interest has attached itself to this subject. Not only were the conclusions which he elicited novel in themselves, but they formed a basis for the enunciation of that interesting “law of alternate generation” with which the famous Danish naturalist’s name will ever remain associated. In all essential particulars Steenstrup’s statements have been verified.

By way of illustrating the phases of development through which the distomes pass I cannot do better than recapitulate in an abridged form the account I have previously given of Distoma (Echinostoma) militare of the snipe and curlew. This account is based on the investigations of Van Beneden, Von Siebold, and Pagenstecher. I regret that it is out of my power to reproduce the illustrations that have already appeared on this head in my introductory treatise (see ‘Entozoa,’ figs. 5 to 9 inclusive). Our Echinostoma militare produces oval-shaped eggs, which give birth to a free ciliated embryo, and this embryo produces a sporocyst or scolex by internal budding. When the sporocyst separates itself from the embryo it presents a very simple appearance, but showing already a cæcal digestive tube. The tail end is fissured, indicating an early stage of formation of caudal appendages. In the next stage we have a well-developed head and body, the tail becoming strongly pronounced. Limb-like caudal lobes project on either side, and an oral sucker makes its appearance in front. This sucker communicates with the œsophageal bulb and passes directly into the digestive cæcum, which contains a variable number of rounded particles. At this stage, also, incompletely developed Cercariæ may be seen in the perivisceral cavity. These Cercariæ are at first shapeless organisms, but after passing through a series of gradations they ultimately assume a definite form, which, in many cases, is sufficiently distinctive to enable us to refer the Cercariæ to particular species of Distoma. The older writers regarded many of the cercarians as adult flukes. In the early state these larvæ are furnished with tails. They may be seen lodged within the cavity of the body of the sporocysts, being twisted and folded in various attitudes. The Cercariæ not only exhibit a cephalic and ventral sucker, but also a dark forked line representing the digestive system. At a still further stage other structures come into view, until the perfect Cercaria displays an oral sucker, a pharyngeal bulb, an œsophagus, two alimentary cæca, a ventral sucker, a water-vascular system consisting of two main excretory ducts, and a contractile vesicle, by means of which the ducts communicate with the external surface. The tail is conspicuous and furnished with a fringe. The alimentary organs conform to the general trematode type, but before passing into the sexually-mature condition other changes are undergone. The Cercariæ part with their tails, and subsequently they encyst themselves on or within the surface of the body of some mollusk. Their pupa condition is thus arrived at. The pupa itself differs from the cercaria in presenting a double crown of hooks surrounding the head, but the other organs correspond with those already described. According to Van Beneden the hooks make their appearance immediately after encystation. In this condition it is next transferred to the intestine of some higher animal, and in this final situation it gradually acquires all those organs the possession of which will entitle it to be called a sexually-mature or adult distome. In the immature fluke we may now discern the mouth, the buccal or cephalic sucker, the pharyngeal bulb, the œsophagus, the digestive cæca, the coronal spines, the contractile vesicle, the aquiferous system of vessels, the matrices of the yelk-forming glands, and also a central mass of cellules, from which all the other reproductive organs will in due time be developed. In the adult Echinostoma militare the upper third of the body is clothed with little spines. Taking this example as illustrative of the ordinary mode of fluke development we find that a change of hosts is necessary, and that in the intermediate state they occupy the bodies of mollusks. Thus, for the continuation of the species, there must needs be a contemporaneity of vertebrate and evertebrate hosts. Surely no reasonable person can ascribe this concurrence to merely fortuitous circumstances. In this connection I may remark that Villot, in his account of the migrations of the trematodes, states that the cercarian forms of Distoma leptosomum and D. brachysomum of Tringa alpina occur in Scrobicularia and Anthura. These parasites are also found encysted in the gizzard of Tringa.

The tapeworms of birds are undoubtedly injurious to their bearers. All the worms appear to be armed with cephalic hooks; at least, such is the case with the species described by Krabbe, who has supplied figures of the hooks drawn to a scale. Dr Krabbe’s beautiful monograph is a perfect model of its kind. In the accompanying figure the hooks have fallen (Fig. 72). On account of the frequency of their occurrence, some persons have supposed that tapeworms are not injurious to their hosts, forgetting that it is not the mere fact of the existence of tapeworms, but their excessive numbers during particular seasons that give rise to avian epizoötics. The same rule holds good with other parasites. Of course, in fledgelings, as also obtains in yearlings amongst our domesticated animals, a very few parasites are sufficient to prove destructive to the bearer. Thus, as regards the so-called “grouse-disease,” during one season it may be due to tapeworms, during another to strongyles, during a third to excessive abundance of both these parasites. Unfortunately, other avian epizoötics, not necessarily due to parasites of any kind, may be mistaken for helminthic epizoöty. The same thing happens amongst quadrupeds. We have, for example, parasitic equine epizoötic outbreaks, and likewise non-helminthic equine epidemics (as in the case of the Egyptian horse plague of 1876). The true nature of any epizoöty can only be determined by competent investigation. That was well shown in the grouse epidemic of 1872. In that epizoöty the greater number of the birds succumbed to the injuries produced by a nematode worm (Strongylus pergracilis, Fig. 73), but, without doubt, the occasional presence of numerous tapeworms (Tænia calva) hastened the consequent fatality. The following table, giving the results of examination of twelve diseased grouse from the Earl of Cawdor’s estate, will show how inconspicuous a part tapeworms played in the epidemic of 1872. For further details I must refer to my brochure on the ‘Grouse Disease,’ and to some other memoirs quoted in the bibliography below.

+----------+-----------+---------------+-----------+----------------+ | No. of | Condition | State of | Tapeworms | Strongyles | | specimen.| of bird. | viscera. | present. | present. | +----------+-----------+---------------+-----------+----------------+ | 1 | Good | Full | None | Abundant. | | 2 | Emaciated | Putrid | Two | Very numerous. | | 3 | Good | Full | None | Abundant. | | 4 | " | " | " | " | | 5 | " | " | One | " | | 6 | " | Shrunken | Two | Very numerous. | | 7 | Emaciated | Much shrunken | None | " | | 8 | Thin | Shrunken | " | " | | 9 | " | " | " | " | | 10 | Emaciated | Distended | Man | " | | 11 | Thin | Rather full | Several | Abundant. | | 12 | " | " | None | Very numerous. | +----------+-----------+---------------+-----------+----------------+

I have said that tapeworms prove fatal to young birds, even to nestlings. A notable instance of this is recorded by Mr Eames. The parasites were examples of Tænia angulata. Apart from the epidemiological aspects of the subject, it is not uninstructive to notice the variety of helminths that infest the common fowl and game birds. Accordingly, I append a similar but more extended list than that previously given in the supplement to my introductory treatise:

Key to Column Headings:

A = Common fowl. E = Red Grouse. B = Pheasant. F = Grey Partridge. C = Capercaillie. G = Red Partridge. D = Black Grouse. H = Quail.

+----------------------------------+---+---+---+---+---+---+---+---+ | Entozoa of game birds and the | A | B | C | D | E | F | G | H | | common fowl. | | | | | | | | | +----------------------------------+---+---+---+---+---+---+---+---+ |Monostoma verrucosum, Zeder | * | | | | | | | | |Distoma oxycephalum, Rudolphi | * | | | | | | | | | " ovatum, Rudolphi | * | | | | | | | | | " lineare, Zeder | * | | | | | | | | | " dilatatum, Miram | * | | | | | | | | | " fuscatum, Rudolphi | | | | | | | | * | |Filaria Mansoni, Cobbold | * | | | | | | | | |Ascaris vesicularis, Froelich | * | * | * | | * | * | | * | | " gibbosa, Rudolphi | * | | | | | | | | | " inflexa, Rudolphi | * | | * | | | | | | | " compar, Schrank | | | | * | * | * | | * | |Spiroptera hamulosa, Diesing | * | | | | | | | | | " helicina, Molin | | | | | | | * | | |Dispharagus nasutus, Dujardin | * | | | | | | | | | " spiralis, Molin | * | | | | | | | | |Strongylus pergracilis, Cobbold | | | | | * | | | | |Sclerostoma syngamus, Diesing | * | * | | | | * | | | |Trichosoma longicolle, Rudolphi | | * | * | * | | * | | | |Tænia malleus, Goeze | * | | | | | | | | | " microps, Diesing | | | * | * | | | | | | " exilis, Dujardin | * | | | | | | | | | " calva, Baird | | | | | * | | | | | " linea, Goeze | | | | | * | * | | * | | " infundibuliformis, Goeze | * | * | | | | | | | |Ligula reptans, Diesing | | | * | | | | | | +----------------------------------+---+---+---+---+---+---+---+---+

In regard to this list I can only afford space to remark that several of the species are possibly mere varieties. Some of the worms are of great interest. It occasionally happens that Distoma ovatum is found in the albumen of the fowl’s egg, and it is even more common to obtain Ascaris inflexa from the same situation. For a recent example I am indebted to Dr Walker, of Peterborough. Spiroptera helicina resides in the feet, occasioning enlargement of the joints and consequent distress to the bearer. Probably the most important in the list is my Strongylus pergracilis. Here I may mention that on the 10th of April, 1878, I received a letter from Dr Manson, of Amoy, announcing his acquaintance with a filaria infesting the eye of the fowl. On the 9th of May I also received from Dr Manson the head of a bird showing examples of the worm. As the species is new to science I have proposed to call it Filaria Mansoni, after the discoverer. The male is 5/8″ and the female 3/4″ in length. Of the injurious nematodes, giving rise to avian epizoöty, probably one of the most destructive is Ascaris maculosa infesting pigeons. On the 9th of October, 1873, I received a letter from Dr J. Alexander Macdonald, of Woburn, Bedfordshire, stating that he had forwarded to me a pigeon which had been found dead on the previous morning. It seems that the owner of the bird had erected a large pigeon-house, and had imported a number of Antwerp smerles, these birds all continuing in a perfect state of health until about a week before the above-mentioned date, when, to use Dr Macdonald’s words “first one and then another was attacked, and so on, until four or five of the pigeons had died after a few hours’ illness.” The suddenness of these attacks not unnaturally suggested poisoning; and, accordingly, says my informant, the owner “had the curiosity to open one of the birds, when, to his astonishment, he found the intestines stuffed with worms.” Two days later I received a letter from Dr Macdonald, stating that several others of the flock had died, and it further appeared to him probable that the daily list of sick and dying would continue to increase. On the 14th of the month three more of the birds were dead. On the 4th of the following November, the same correspondent obligingly informed me that the epidemic had been “at last mastered.” It seems that altogether twelve birds had perished. On the 9th of October one of the birds was carefully examined by me, and the results were so interesting that I am constrained to give a few of the particulars originally communicated to the Zoological Society. As stated in my paper, the whole intestinal tract of the dead bird was crowded with these ascarides. The small intestine was inflamed throughout, and showed several large ulcerated patches; nevertheless, there were no traces of emaciation. From this it was evident that the parasites had grown quickly, the malady having a correspondingly rapid formation. The distribution of the parasites was curious. One specimen, two inches long, reached from the crop to the proventriculus. The cavities of this organ and of the gizzard were crammed with worms completely blocking the passage. Three of the worms had also placed themselves within the pyloric opening, their bodies partly lodging within the duodenum. The duodenum itself was crowded with worms, their numbers somewhat decreasing downwards. I removed thirty-six worms from the œsophagus, proventriculus, and stomach, besides 166 others from the intestinal canal, thus obtaining a total of no less than 202 nematodes from this small host. Considering the large size of these entozoa, the extent of infection must be pronounced remarkable. The largest females measured 2-1/2″ in length. One of the most interesting facts--serving to exemplify a well-known habit of lumbricoid worms generally--consisted in the circumstance that two of the parasites had succeeded in perforating the horny lining membrane of the gizzard. The injuries had been accomplished during the life of the host, for the walls of the gizzard were inflamed opposite the perforations. There was a little half digested food within the stomach, the débris of which, when placed under the microscope, showed several ova. There were no free embryos, neither had the development of the freed eggs proceeded beyond yelk-segmentation. Free eggs were also found both in the small and large intestine. The eggs measured about 1/360″ by 1/700″ in diameter. Referring to my paper for further anatomical details, I can only add that, despite these facts, the ascarides in question do not appear to be a very frequent source of epizoöty. It was remarked by Dujardin that Heister, at Rostok, and Gebauer, at Breslau, found this parasite abundant at the beginning of the eighteenth century; but, according to examinations conducted at Vienna, the worm was found in the common pigeon in only eleven instances out of 245, and thrice only in thirty-eight examples of the ring-dove; moreover, the examination of eighty-seven other pigeons and doves of different species yielded entirely negative results. The Dublin helminthologist, Bellingham, noticed the occurrence of this parasite in Ireland.

Any attempt so much as to enumerate the species of nematoids infesting birds would carry me far beyond the aim and scope of this treatise. One of the commonest species is Ascaris (Heterakis) vesicularis. Many hundreds of forms have been described by Dujardin, Diesing, Molin, Krabbe, and other systematists, and it remains for some future laborer to condense the facts which are dispersed throughout a very wide-spread literature. As regards the particular species of nematoids that are either actually known or conjectured to be injurious to birds I can only find space to repeat some of the particulars which I have elsewhere recorded in respect of Sclerostoma syngamus. In 1799 a letter from Dr Wiesenthal, of Baltimore, U.S., was published in the ‘Medical and Physical Journal,’ containing an account of a parasite infesting the trachea of fowls and turkeys in America. The communication is dated May 21st, 1797, and is the first public record concerning the entozoon. Dr Wiesenthal says: “There is a disease prevalent among the gallinaceous poultry in this country, called the gapes, which destroys eight-tenths of our fowls in many parts, and takes place in the greatest degree among the young turkeys and chickens bred upon old-established farms. Chicks and poults, in a few days after they are hatched, are found frequently to open their mouths wide and gasp for breath, at the same time frequently sneezing and attempting to swallow. At first the affection is slight, but gradually becomes more and more oppressive, and it ultimately destroys. Very few recover; they languish, grow dispirited, droop, and die. It is generally known that these symptoms are occasioned by worms in the trachea. I have seen the whole [windpipe] completely filled with these worms, and have been astonished at the animals being capable of respiration under such circumstances.”

Any one who has witnessed the gapes will at once recognise the accuracy of Wiesenthal’s description; and so far as the phenomena of the disease are concerned, very little more has been added in the numerous accounts which have since appeared. On the 1st of August, 1808, the English naturalist, George Montagu, communicated to the Wernerian Society a paper entitled “Account of a species of Fasciola which infests the trachea of poultry, with a mode of cure.” Montagu does not appear to have been aware of the existence of any previous record. He gave a scientific description of the parasite, which led to its being noticed in the systematic works of Rudolphi, Dujardin, and Diesing, but the best accounts of the worm are due to Von Siebold. Sclerostoma syngamus has been found in the trachea of the turkey, domestic cock, pheasant, partridge, black stork, magpie, hooded crow, green woodpecker, starling, and swift. In July, 1860, I obtained a fowl suffering from the gapes, and operated upon it in the following manner:--A small portion of wool having been dipped in chloroform and placed in front of the nostrils the bird soon became insensible. The skin of the neck was then divided and the trachea slit up to the extent of a quarter of an inch. With a pair of common dissecting forceps, I removed seven Sclerostomata. Six of these parasites were sexually united, the odd worm being a female. After I had closed the external wound with a single thread the bird woke out of its artificial sleep, when it soon recovered its legs, and ran about the table vigorously. Moreover, in a very few minutes it devoured the contents of a saucer partly filled with bread and milk. An occasional gape was caused by an accumulation of frothy mucus within the injured trachea, but this obstruction the bird soon got rid of by shakes of the head and sneezing. The only subsequent inconvenience to the bird arose from emphysematous distension of the cellular tissue of the head and neck. This was relieved by puncture, the emphysema ceasing to form after the external wound had healed. Some months afterwards I destroyed the bird, and on dissecting the neck, a distinct cicatrix was found indicating the site of the operation on the trachea. The divided cartilaginous rings, six in number, were united only by a thin layer of connective tissue. The female worms gave an average length of 5/8″, the males scarcely exceeding 1/3″. The mouth is furnished with six prominent chitinous lips. In both sexes the surface of the body is quite smooth, but the tail of the female exhibits a tendency to fold upon itself. The lower part of the body suddenly contracts to form a short, narrow, mucronate, pointed tail. The male is usually found rigidly affixed by means of a strong, membranous, sucker-like bursa, which proceeds from the lower end of its body. In regard to the peculiar mode of union of the sexes, it becomes an interesting point to ascertain whether there be an actual incorporation of the substance of the copulatory organs during or after the act of impregnation. In my specimens none of the three pairs were organically united, and I succeeded in separating one pair very readily. Dujardin speaks of them as being soldered together, whilst the statements of Von Siebold are still more explicit. In connection with this subject the latter observer makes the following comment (‘Wiegmann’s Archiv,’ 1836, s. 106):--“The two sexes of almost all round worms are united only at the time of copulation. The male of Heteroura androphora has also the habit of remaining connected with its mate beyond the period of copulation; here, thus, there is a continuous union of the sexes without a growing together; and in Syngamus trachealis there is ultimately a lasting continuity of the sexes by means of an actual growing together.” Having confidence in Von Siebold’s statement, I concluded that the sexual union in my specimens had only recently been effected. Admitting this to have been the case, one naturally asks how the mature eggs can make their escape. Clearly, the eggs can only escape by an eventual breaking up of the body of the parent. The eggs of Sclerostoma syngamus are comparatively large, measuring 1/250″ in length. Many of the ova contained fully formed embryos, and in the centre of the lower third of the body of one of them I perceived an undulating, imperfectly formed intestinal tube. By whatever mode the young escape the shell, it is clear that they are already sufficiently developed to undertake an active migration. A change of hosts is probably necessary, but in the first instance they either enter the substance of fungi or other vegetable matters, or they bury themselves in the soil at a short distance from the surface. In view of checking the destructive influences of this parasite, the following methods have been recommended.

First. The simplest plan consists, as Dr Wiesenthal long ago pointed out, in stripping a feather from the tube to near the narrow end of the shaft, leaving only a few uninjured webs at the tip. The bird being secured, the webbed extremity of the feather is introduced into the windpipe. It is then twisted round a few times and withdrawn, when the worms are found attached. In some instances this plan succeeds entirely.

Secondly. The above method is rendered more effectual when the feather is previously steeped in some medicated solution which will destroy the worms. Mr Bartlett employs salt for this purpose, or a weak infusion of tobacco; and he informs me that the simple application of turpentine to the throat externally is sufficient to kill the worms. It should be borne in mind that the bird itself may be injuriously affected by these drugs if they are carelessly employed.

Thirdly. The treatment recommended by Mr Montagu proved successful in his hands, although the infested birds were old partridges. One of his birds had died of suffocation; but he tells us that “change of food and change of place, together with the infusion of rue and garlic, instead of plain water, to drink, and chiefly hemp-seed, independent of the green vegetables which the grass plot of the menagerie afforded, recovered the others in a very short time.”

Fourthly. The plan I employed in my experiment. This is only desirable in advanced cases, where suffocation is impending. It will afford instant relief, as the trachea may be cleared of all parasitic obstructions.

Lastly. The essential point to be observed is the total destruction of the worms. This will help to put a stop to future epizoöties. If the parasites are merely killed and thrown away carelessly, the eggs will sustain no injury. Decomposition having set in, the young embryos will sooner or later escape their shells, migrate in the soil or elsewhere, and ultimately find their way into the air-passages of birds in the same manner as their parents did before them.

In this place I must not omit to mention the remarkable circumstance, quoted in my pamphlet on the grouse disease, that Prof. Wyman, of Boston, found Eustrongyli surrounding the cerebellum in seventeen out of nineteen snake-birds or water-turkeys that had been shot in Florida. These viviparous nematodes apparently occasion their avian bearers no inconvenience. No doubt, as Wyman observes, their presence must be regarded as a normal state of things: but should they occur in excessive numbers, then we can hardly doubt the result.

As regards acanthocephalous parasites, although not so numerous as the nematodes, it is extremely probable that they play a similar rôle. Parasites which prove fatal to swine are scarcely likely to be harmless in birds. On the 18th of February, 1875, I received from Sir Joseph Hooker eleven worms for identification. Mr Charles P. Hooker, his son, subsequently informed me by letter that he had found them in a Redwing (Turdus iliacus) which he dissected in January, 1875. The worms (Echinorhynchus transversus) occupied the large intestine, probably to the number of one hundred in all. Hitherto this parasite has been found abundantly in the blackbird, thrush, and in most of the Turdidæ; but not in the redwing. It has also been obtained from the starling and red-breast. The presence of so many of these armed parasites in one small host could hardly fail to inflict severe injury on the bearer.

In concluding this section of my work I can only find space to make a few acknowledgments. Most of the rare, new, or interesting avian entozoa which I have examined and described have been received either from the Zoological Gardens, or from personal friends. In particular I may mention the collections sent to me by Mr Charles Darwin, Mr Robert Swinhoe, Mr Charles W. Devis, Dr Murie, Dr John Anderson, and Mr Spooner Hart, of Calcutta. A great many correspondents have contributed single specimens, many of which I have already incidentally acknowledged in these pages. In this place I must particularise the new species (Ascaris Cornelyi) which I described from specimens sent to Mr Sclater. This worm infests the vulturine pintado (Numida vulturina). Mr Darwin’s collection contained fine examples of Filaria horrida from the American ostrich (Rhea). When dissecting birds at the Zoological Society’s Menagerie, I obtained (in addition to the parasites already mentioned) Distoma æquale from the American owl (Strix perlata); Tænia multiformis from the night heron (Ardea nyctocorax); T. infundibuliformis from a horned pheasant (Phasianus); T. lævis and T. lanceolata and also Ascaris tribothrioides from a dusky duck (Anas obscura); Eustrongylus papillosus (fig. 75) from the larus crane (Grus antigone); Trichosoma longicolle from the horned pheasant, and T. brevicolle from the Sandwich Island goose (Bernicla Sandwichensis). This bird was also infested by Spiroptera crassicauda and Ascaris dispar. From the ring-necked pheasant (Ph. torquatus) and from the black-backed Kaleege (Euplocomus melanotus), and also from a cheer pheasant (Ph. Wallichii), I obtained abundance of Ascaris vesicularis. From the ashy-headed goose (Chloephaga poliocephala) examples of Str. tubifex and Str. nodularis. This bird also yielded a new species (Str. acuticaudatus). From a tinamou (Tinamus) I obtained the Ascaris strongylina of Rudolphi (Str. spiculatus, mihi). From amongst our British birds I have obtained Asc. depressa, Trichosoma falconum and Hemistoma spathulum, from the kite (Falco milvus). Of these three worms, the last named was also found in the long-eared owl (Strix otus), whilst the first likewise occurred in a kestrel (Falco tinnunculus) and in a honey buzzard (Pernis apivorus). I may add Filaria attenuata from a peregrine (F. peregrinus); and F. leptoptera from a sparrow hawk (Accipiter nisus). From the redshank (Totanus calidris) I obtained Tænia variabilis, and from the curlew (Numenius arcuata) T. sphærophora; and from various gulls (Larus glaucus and L. tridactylus) the Tetrabothrium cylindraceum. Also from the grey gull Echinostoma spinulosum. From the red-throated diver I procured Tetr. macrocephalum. I found this tapeworm also in the guillemot (Uria troile), together with a nematode (Ascaris spiculigera) two examples of which were lodged in the right auricle of the heart. From a capercaillie (Tetrao urogallus) I have obtained a species of Ligula, and likewise numerous examples of Trichosoma longicolle. Of necessity, this brief notice only comprises a small part of the avian entozoa contained in my collection, many of which I have not had time to describe, whilst, as regards others, I can only say that they remain in abeyance for examination and identification.

Mr Brotherston has recently recorded an interesting find (made Nov. 25th, 1874) of nematodes in the legs of the lesser grebe (Podiceps minor), and also (Feb. 27th, 1878) in the waterhen (Gallinula chloropus). Both limbs of both birds were infested. The worms of the grebe were spirally coiled amongst the muscles and tendons near the lower end of the tibia, and when unrolled measured about an inch in length. The parasites of the waterhen were similar in appearance. Not improbably these were all sexually-imperfect female examples of Filaria acuta hitherto found in the abdomen of grebes.

The British Museum contains many interesting specimens purchased from the collection of Von Siebold, but they are practically inaccessible to investigators. The entozoa in the Hunterian Collection, though few in number, are in an excellent state of preservation, and at all times accessible to visitors.

The ectozoa of birds are too numerous to be dealt with in these pages. References to recent papers by Haller, Mégnin, and Westwood will be found below. The insects infesting the domestic fowl have been alluded to in connection with the occurrence of poultry-lousiness in the horse.

BIBLIOGRAPHY (No. 57).--(Anonymous), “On the (gape) Diseases of Fowls,” the ‘Veterinarian,’ p. 267, 1841.--(Anon., initialed “Q.”), Letter on the “Grouse Disease,” in the ‘Times,’ Sept. 5, 1874.--(Anon.), “On Grouse and Partridge Disease,” being annotations in the ‘Lancet,’ Sept. 4, 1875, pp. 360 and 361.--(Anon.), “Grouse Disease,” letter signed “R.” (probably from Lord Ravensworth), in ‘Land and Water,’ Aug. 16, 1873.--(Anon.), “Grouse Disease,” article (from “W. C.”) in the ‘Field,’ Aug. 2, 1873 (criticising my brochure.--T. S. C.).--Arlong, “Note on Tænia from the Fowl,” ‘Rec. Méd. Vét.,’ 1875.--Baird, W., “Descr. of Tænia calva from the Grouse,” in ‘Brit. Mus. Catalogue,’ p. 83.--Blavette, “Descr. of a Verminous Disease among Fowls,” ‘Veterinarian,’ p. 649, 1840.--Brotherston, A., “Parasitic Worms in Legs of Grebe (Podiceps minor) and Water-hen (Gallinula chloropus),” ‘Science Gossip’ for April, 1878, p. 88, and in ‘Proceedings of the Berwickshire Naturalists’ Club,’ vol. viii, p. 288.--Carter, B. (see Cobbold).--Chapman, H. C., “Description of a new Tapeworm from Rhea,” ‘Proceed. Phil. Acad.,’ 1876, p. 14.--Chatin, J., “Étude sur des helminthes nouveaux ou peu connus (treating of a Cyathostoma, from Anas tadorna and Sclerostoma pelecani),” ‘Annales des Sciences Naturelles,’ 1875.--Cobbold, ‘The Grouse Disease, a statement of facts tending to prove the Parasitic Origin of the Epidemic,’ London, 1874.--Idem, Letter in the ‘Field,’ Sept. 9, 1872.--Idem, “Contributions to our Knowledge of the Grouse Disease, with description of a new Species of Entozoon,” ‘Veterinarian,’ March, 1873; see also an article (by Brudenell Carter) in the ‘Times’ for Sept. 5, 1874; repr. in the ‘Veter.,’ Oct., 1874.--Idem, “Remarks on the Entozoa of the Common Fowl and of Game-birds, especially in relation to the Grouse Disease,” the ‘Field,’ Sept. 14, 1867, and ‘Brit. Assoc. Rep.,’ 1867.--Idem, “On Sclerostoma and the Disease it occasions in Birds,” ‘Linn. Soc. Proc.,’ 1861; repr. in the ‘Field,’ June 22, 1861, and in ‘Edin. Vet. Rev.,’ vol. iii, p. 439, 1861, also in Tegetmeier’s work on ‘Poultry;’ see also a comment on “Gapes,” by “Umbra,” in the ‘Field,’ June 29, 1861.--Idem, “Parasites from the Zoological Gardens,” ‘Intellectual Observer,’ 1862.--Idem., “Notes on Entozoa (species Nos. 1, 7, 9, 12),” in ‘Zool. Soc. Proc.,’ 1873-76.--Idem, ‘Linn. Soc. Trans.,’ 1858.--Idem, “On Entozoa of Birds and Fishes, collected by Mr Charles W. Devis,” ‘Zool. Soc. Proc.,’ 1865.--Idem, “Note on Entozoa in the Crested Grebe,” the ‘Field,’ March 29, 1873.--Colquhoun, W., ‘Remarks on the decrease of Grouse, and on the Grouse Disease (Gapes),’ Edinburgh, 1858; see also a notice in ‘Edin. Vet. Rev.,’ vol. i, April, 1859.--Crisp, E., “Note on Hydatids in an old Honduras Turkey,” ‘Path. Soc. Trans.,’ 1863.--Idem, “On Sclerostoma,” ‘Rep. of Path. Soc.,’ in ‘Med. Times and Gaz.,’ Oct. 26, 1876, p. 474.--Idem, “Note on Filaria in the Heart of a Peregrine Falcon,” ‘Path. Soc. Trans.,’ 1854.--Davaine, ‘Syngame de la trachée,’ p. 37, and ‘Synops.’ cxiv, in his ‘Traité.’--Devis, C. W. (see Cobbold).--Diesing, ‘Revis. der Myzelminthen,’ Abtheil. “Trémat.,” 1858.--Idem, “Tapeworm from Podiceps,” in his ‘Zwanzig Arten von Cephalocotyleen,’ Wien, 1856.--Idem, see various species in his ‘Revisionen,’ given in Bibl. No. 58.--Eames, C. J. L., “On Tapeworm in Blackbirds,” letter to the ‘Lancet,’ June 9, 1877, p. 863.--Farquharson, R., “The Grouse Disease (due to a contagious fever),” letter to the ‘Lancet,’ Sept., 1874.--Fergusson, J., “On Grouse Disease,” letter in the ‘Times,’ July 16, 1878.--Gentles, T. W., “Tapeworm in Birds,” letter to the ‘Lancet,’ Jan. 18, 1868, p. 106.--Haller, G., “Freyana und Picobia, zwei neue Milbengattungen,” in ‘Sieb. u. Köll. Zeitsch.,’ 1877, s. 181.--Johnston, D., “On the Grouse Disease,” letter in the ‘Lancet,’ Sept. 20, 1873, p. 441.--Krabbe, ‘Bidrag til Kundskab om Fuglenes Bændelorme,’ Copenhagen, 1869 (contains a summary in French, ‘Recherches sur les Ténias des Oiseaux’).--Linstow, O. von, “Euthelminthologica” (containing descriptions and notes on worms from birds, fishes, reptiles, and mollusks), ‘Archiv für Naturgeschichte,’ 1877.--Idem, “New Flukes (Dist. vitellatum and D. macrophallus) from Totanus hypoleucus, and D. cælebs from Fringilla,” Beobacht. in ‘Arch. f. Naturg.,’ 1875, s. 189-193.--Maclagan, “Note on the Grouse Disease,” ‘Proc. Roy. Soc. of Edin.,’ April 20, 1874, p. 378.--Marion, “Révis. des Némat. du Golfe de Marseilles,” ‘Compt. Rendus,’ 1875.--Mégnin, P., “On Harpirhynchus and other Mites,” in ‘Rev. f. Thierheilk.,’ Oct., 1878, s. 146.--Idem, “Mémoire sur les Cheylétides Parasites (Picobia, &c.),” ‘Journ. d’Anat. et de Physiol.,’ 1878; see also ‘Rev. f. Thierheilk.,’ Sept., 1878 et seq.--Molin, in his various monographs (quoted in Bibl. Nos. 54, 56, and elsewhere).--Montagu, G., “Account of a species of Fasciola which infests the Trachea of Poultry, with a mode of Cure,” ‘Memoirs of the Wernerian Nat. Hist. Soc.,’ vol. i, p. 194, 1811.--Perrier, ‘On Syngamus’ (brochure, Paris, 1875).--Pulteney, R., “On Ascarides discovered in Pelicanus carbo and P. cristatus,” ‘Linn. Trans.,’ vol. v, 1800, p. 24.--Röll, “Beitrag. zur Entwickelungsgeschichte der Tænien,” ‘Verh. d. Würzb. p. m. Ges.,’ Bd. iii, 1852, s. 51.--Sanderson, J. B., “On Grouse Disease,” ‘Brit. Med. Journ.,’ May 15, 1875.--Small, M., “Worms in the Eyes of Geese,” from the ‘Irish Farmer’s Gaz.,’ in the ‘Veterinarian,’ 1862, p. 19.--Tait, L., “Tapeworm in Birds,” letters to the ‘Lancet’ for Jan. 25, 1868, p. 145, and Feb. 8, 1868, p. 214; see also “Pediculus,” ibid., p. 180.--Tegetmeier, “On the Grouse Disease,” in the ‘Field,’ Sept. 12, 1874.--Thick, “Letter on the Cure of Gapes,” in ‘Land and Water,’ Aug., 1867, p. 77.--Vaughan, “The Grouse Disease,” in the ‘Field,’ Aug. 23, 1873.--Villow, A., “Sur les migrations, et les Métamorphoses des Trematodes,” ‘Comptes Rendus,’ 1875, and ‘Ann. Nat. Hist.,’ 1875 (chiefly on flukes of the sea-lark, Tringa alpina).--Idem, “Sur le syst. nerveau,” &c., ibid., 1875.--Idem, “On the Helm. Fauna of the Coast of Brittany (chiefly from birds),” ‘Ann. Nat. Hist.,’ from ‘Comp. Rend.,’ 1875, p. 1098, and from ‘Arch. de Zool. Expérim. et gén.,’ 1875.--Idem, “Sur l’appareil des Trematodes (Dist. insigne),” ‘Compt. Rend.,’ 1875.--Wedl, K., ‘Anatomische Beobachtungen ueber Trematoden,’ Wien, 1858 (contains excellent descriptions of numerous flukes, chiefly from birds).--Westwood, J. O., “New Flea on a Fowl (Sarcopsillus),” ‘Entom. Month. Mag.,’ xi, p. 246, 1875.--Wiesenthal, A., “Account of a Parasite infesting the Trachea of Fowls and Turkeys in America,” ‘Med. and Phys. Journ.,’ vol. ii, p. 204, 1799.--Wyman, “On Eustrongyli within the Cranium of Water-Turkeys,” ‘Proc. Boston Nat. Hist. Soc.,’ 1868.--Youatt, “On a Verminous Disease in Poultry” (being a letter to him), ‘Veterinarian,’ p. 648, 1840.--Zeller, “On Leucochloridium,” from ‘Zeitsch. f. wissensch. Zool.,’ 1874, s. 564, and from ‘Bibl. Univ. Bullet. Sci.,’ 1874, p. 366, in ‘Ann. Nat. Hist.,’ Feb., 1875.

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