A practical guide to the study of the diseases of the eye: their medical and surgical treatment

Preface

"We are not unprovided with works on the diseases of the eye ; but they are either so elaborately complete as to require a high degree of education, and large experience in ophthalmic practice, to enable the reader to appreciate the nice distinctions laid down ; or they attempt too much within narrow limits, and, from want of space and confused arrangement, sacrifice that clearness of description which should be regarded as all-important in a work intended for instruction.

In offering this treatise to the profession, and to those who are about to enter it, the author does not assume to set forth all which is known in respect to diseases of the eye. He has endeavored to supply a want which his relations with junior practitioners and students have shown him to exist, and to prepare a work which shall afford, in a form

IV PREFACE.

as simple and concise as possible, a practical and serviceable knowledge of these diseases, and of their treatment, to those whose opportunities for special study have been less extensive than they could have desired. It is only in a few cities, in America, that students find even limited facilities for clinical observation of these affections; and a very large number yearly begin their career as practitioners, without having enjoyed the privilege of any instruction whatever in this important branch of medical education.

It has been the aim of the author to avoid encumbering his work, and confusing the reader, by the introduction of merely exceptional details, — by an account of every jDroposed but exploded mode of treatment, or by more than the most sparing use of the too learned technical designations which abound in ophthalmic literature ; but he has endeavored to give clear and explicit descriptions of the usual forms of disease, so that the physician may be able to recognize, at once, their distinctive features, — and to define the course of treatment best adapted, in a majority of cases, to remove the morbid con-

TREFACE. V

dition. Some affections, and certain phases of disease, of rare occurrence and trivial importance, will be merely alluded to ; enough being said, however, to enable the reader to detect their character, as exceptional cases, and to allow him to consult other works, at his leisure, should he wish for complete information reswrdhw them.

It is impossible for the author of a medical work to avoid availing himself of the rich treasures accumulated as the result of the labors of his predecessors. To all of them the writer acknowledges his indebtedness. But he would not have assumed his task, except from a desire to fulfil the duty which he believes to be incumbent on every physician, of adding something, if possible, to the stock of knowledge which it is the glory of our profession to regard as the common property of all its members. He has hoped to do this, by promulgating new and original views, which he deems highly important, upon certain of the subjects considered in this treatise, — and by facilitating, by simplified classification, the study of what at first sight seem to be the intricate and compli-

VI PREFACE.

cated phenomena of diseases of the organ of vision.

The descriptions given, the conclusions announced, and the treatment recommended, are such as the author's own observation and experience have led him to consider accurate and useful.

Chapter I. Method Op Examining The Eye

The Physician's own Observation to be chiefly relied on, 3. — Examination of the Appendages of the Eye, 4; of the Surface of the Globe, 5 ; of internal Surface of Lids, 5 ; of internal Parts of the Eye, 6. — Mode of everting the Upper Lid, 8. — Examination in Children, 8. — Varieties of Injection as a Means of Diagnosis, 10. — Differences in the Secretions, 10. — Differences in Pain, 11. — Importance of these Symptoms in the Classification of Diseases, 11.

Chapter II. The Ophthalmoscope

Description of, 12. — Manner of using, 14.

CHAPTER ni.

REMEDIES AND THEIR APPLICATION.

Some Affections require only local Applications, 15. — Others demand Constitutional Treatment, 15. — Solutions preferable as Collyria, 15. — Ointments should never be used, 16. — Danger of employing Preparations containing Lead, 16. — Too free Use of Nitrate of Silver, 17. — The Sulphate of Copper in Form of Crayon, 18. — Mode of using Crayon, 19. — Manner of introducing Collyria, 20. — Depletion by Leeches, 20. — Scarification seldom useful, 21. — Inutility of Division of Vessels running upon Cornea, 21. — Tonic Treatment compatible with local Depletion, 21. — Poultices often hurtful, 22. — Collyria have little Effect ou Inflammations of internal Parts, 22. — Sedatives, 22.

Chapter IV. Affections Of The Conjunctiva

Simple Conjunctivitis, 24; caused by Foreign Particles, 24; by Draughts of Air, 26. — Removal of Foreign Bodies, 25. — Eruptive

Vlll TABLE OF CONTENTS.

Conjunctivitis, 27. — Papula? on Conjunctiva and Cornea, 27. — Flattened Papulae, 27. — Change of Air useful, 28. — Mucopurulent Conjunctivitis, 28. — Catarrhal Conjunctivitis, 29. — Frequently sudden in Access, 29. — Lids first implicated, 29. — Disease extends to Globe, 30. — Granulations, 30. — Upper Half of Cornea often cloudy from Friotion of Granulations, 31. — Kind of Pain, 32. — Form of Injection, 32. — Inoculation a frequent Cause, 33. — Importance of effecting a complete, Cure, 34. — Slow Eecovery of in Cases of very long standing, 35. — Results of Ulceration of Cornea, 36. — Tonic Treatment essential in many Cases, 37. — Cleanliness essential, 39. — Perseverance in Treatment, 41. — Purulent Conjunctivitis, 43. — Contagiousness of, 43. — Chemosis, 44. — Gentle Treatment better than Heroic Measures, 47. — Common in Armies,

47. — Gonorrheal Conjunctivitis, 47. — Extreme Violence of,

48. — Most common in Males, 48. — Rapid Fatality of, 48 — Conjunctivitis of new-born Infants, 50. — Generally supervenes a few Days after Birth, 51. — Enormous Amount of Discharge, 51. — Danger of Perforation of Cornea requires Vigilance, 51. — Use of an Elevator to raise Lids, 53. — Harsh Remedies to be avoided, 54. — Atropja to be used if Cornea becomes implicated, 56. — Pterygium. 56. — Not a merely temporary Enlargement of Vessels, 57. — Removal of, 58. — Ecchymosis, 58. — (Edema, 59. — Warty Growths, Cysticerci, 60.

Chapter V

affections of the lachrymal organs.

Eversion of Puncta Lachrymalia, 61. — Thickening of Lining of Passages, 62. — Obstruction of Duct, 62. — Abscess of Sac, 63. — Fistula Lachrymalis, 63. — Canulae and Styles to be rarely inserted, 66. — Introduction of a large-sized Probe through the previously enlarged Punctum, 67. — Means of relieving Abscess without the Lancet, 69. — Treatment of Actual Fistula, 70.

Chapter VI

traumatic injuries of the eye.

Over Activity in Treatment too common, 72. — Injuries of Cornea and Conjunctiva, 73. — From Beard of Grain, 73. — Chemical Injuries, 74. — Burns, 74. — When complicated with Hernia of Iris, 76. — Wounds of Eyelids, 76. — Wounds of Sclerotica, 78. — Wounds of Crystalline Lens, 78. — Dislocation of Lens, 80. — Injuries of the Iris, 81. — Injuries from Percussion-Caps, 81; from penetrating Bits of Steel, 81. — Foreign Bodies in interior of Eye, 82. — Sympathetic Inflammation of other Eye, 85.

TABLE OF CONTENTS. IX

CHATTER VII.

AFFECTIONS OF THE CORNEA.

Ulckkation of the Cornea, 88. — Generally met with in Children of strumous Diathesis, 88. — Child fretful and feverish, 88. — Photophobia, 88. — Tact required in examining the Patient, 89. — Ulcers most often central, 93 ; accompanied by Disease of Meibomian Glands, 98. — Dotted Opacity, 100. — Corneitis, 102; often a Symptom of inherited Syphilis, 103; frequently conjoined with Iritis, 104. — Opacities, 107; sometimes accompanying actual Disease, at other Times the Result of former Ulceration, 107. — Deposits of Lead, 108. — Arcus Senilis, 109. — Conical Cornea, 110. — Foreign Bodies in Cornea, 113. — Stapyhyloma, 114.

CHATTER VIII.

AFFECTIONS OF THE SCLEROTICA.

Wounds of the Sclerotica, 117 ; Incised, 117. — Rupture, 117. — Protrusion of Lens through, 117. — Thinning, 118. — Staphyloma.

CHATTER IX.

affections of the iris.

Tolerance of Injuries, 121. — Rheumatic Iritis, 122. — Characteristic Pain, 122. — Peculiar Injection, 123. — Copious Lachrymal Secretion, 123. — Intolerance of Light, 123. — Puffy Appearance of Iris, 124. — Contraction of Pupil, 124. — Slow Recovery of Vision, 125. — Self-limited in some Cases, 126. — Liable to Continuance and Complication if the Symptoms are neglected or exceed a certain Degree, 126. — Great Importance of preventing Adhesions by maintaining Dilatation of the Pupil, 126. — Examination of the Value of Mercury in Treatment of Iritis, 127. — Anatomical Reasons for Value of Belladonna, 129. — Detachment of Adhesions when formed, 136. — Syphilitic Iritis, 137. — Congenital Syphilitic Iritis, 139.

CHAPTER X. affections of the crystalline lens.

Dislocation, 140. — Spontaneous Dislocation, 140. — Cataract,

143. — Congenital Cataract, 143. — Oscillation of Globe, 144. — Hereditary Predisposition, 144. — Numerous Cases in one Family,

144. — Time required for Absorption after Operation, 148. — Traumatic Cataract, 149. — Lenticular Cataract, 152. — Most com-

X TABLE OF CONTENTS.

mon in advanced Age, 152. — Hard Cataract, 153. — Nuclear Cataract, 153. — Soft Cataract, 153. — Cortical Cataract, 153. — Hereditary- Tendency to at about a certain Age, 153. — Belladonna employed by Charlatans for a pretended Cure, 155 — Cloudiness may commence in the Nucleus or in the Cortical Portion of Lens, 156. — No Treatment except by Operation of any Avail, 158. — Time for Operating, 159. — Operation on one or both Eyes, 159. — Preparation for Operation, 160. — Modes of Operating, 160. — Cataract-Glasses, 176. — Secondary Operations for Cataract, 177. — Glaucomatous Cataract, 179.

CHAPTER XL

affections of the titreous humor.

Softening of the Vitreous, 180. — Sparkling Stnchisis, 180. — Crystals of Cholesterine, 180.

CHAPTER XH.

operations for artificial pupil.

When called for, 182. — Conditions Requisite to Success, 182.

CHAPTER Xni. affections involving the entire globe.

Glaucoma, 188. — Operations for Glaucoma, 189. — Hydrophthalmia, 192. — Paracentesis. 193. — Cancer, 193. — Encephaloid, 193. — Melanosis, 195. — Scirrhus, 196. — Ophthalmitis 196; sometimes one of the Sequelae of Fever, Phlebitis, or the Puerperal Condition, 197. — Pus developed behind the Globe, within the Ocular Capsule, may simulate Phlegmon of the Globe, 198. — Sympathetic Ophthalmia ; may come on a long Time after the other Eye has recovered from Traumatic Injury, 200. — Sluggish Changes in deep-seated Parts of the Eye, 201. — Operation for removing the Eyeball, 202.

CHAPTER XIV.

artificial eyes.

Should correspond with other Eye, and be suitable Size for the Cavity in which they are to be worn, 206. — To be removed at Night, 207. — Mode of inserting and removing, 208. — Adhesions between Lids and Globe not to be rashly divided, 209. — Eye not to be worn if it loses its Polish, 208.

TABLE OF CONTENTS. XI

CHAPTER XV.

affections of the choroid.

Inflammation, 211. — Hemorrhage, 212. — Serous Effusion, 213. — Absence of Pigment-Cells, 213.

CHAPTER XVI. affections of the retina.

Inflammation, 215. — Apoplexy, 215. — Anh^emia, 216. — Fatty Disease. Separation from Choroid, 216. — Encephaloid, 217.

CHAPTER XVII.

amaurotic affections.

Vagueness of Term " Amaurosis," 219. — Dilatation of Pupil may exist without Loss of Vision, 220. — Disposition of Patients to deceive themselves into a Belief that they are gaining, when such is not the Case, 226.

CHAPTER XVIII.

temporary affections of vision.

Night Blindness, 227. — Loss of Vision during Pregnancy or Lactation, 228.

CHAPTER XIX.

peculiarities of vision.

Inability to distinguish Colors, 230. — Increased Sensibility to Light and Acuteness of Vision. Sometimes simulated, 234. — Musc.e Volitantes, 234; often observed by healthy Eyes, 235; seldom entirely got rid of, but do not lead to Blindness, 236. — Double Vision, 237. — Sometimes a Result of Paralysis of Muscles of Eye, 237. — Sometimes merely an Effect of Debility, 237. — Spectral Illusions, 237.

CHAPTER XX.

affections of the adaptive power of the eye.

Mechanism of the Changes of Refraction, 239. — Short-sightedness, 240; sometimes a Symptom of other Disease in the Eye, 240; not often congenital, 241. — Rules in regard to Eye-Glasses or Spectacles, 243. — Glasses should not be stronger than absolutely needed,

Xll TABLE OF CONTEXTS.

246. — Long-sightedness, 247 ; increased by improper Use of Eves, or by wearing Glasses when not required, 248. — Glasses should not be assumed too soon nor avoided too long, 249.

CHAPTER XXI.

CHAPTER XXTT.

ASTHENOPIA.

Weariness and Pain after too long continued use, 260. — Measles and other Diseases a frequent Cause, 261. — Use of the Eyes not to be absolutely forbidden, 264. — Glasses sometimes of apparent Assistance, but should not be hastily advised, 267.

CHAPTER XXin.

AFFECTIONS OF THE MUSCLES OF THE ETEBALL.

Strabismus, 269. — Most often convergent, 269. — Vision often less good in the Eye most affected, 270. — Operations for Strabismus 273. — Paralysis of the Muscles of the Eye, 281. — Paralysis of the Third Pair of Nerves, 281. — Various Branches may be implicated, 282. — Mydriasis, 283. — Vision good if the Size of the Pupil be lessened, 283. — Paralysis of the Sixth Paie, 285. — Paralysis of the Fourth Pair, 285.

CHAPTER XXIV. affections of the eyelids.

Falling of the upper Lid, 2S7. — (Edema, 288. — Inflammation, 289. — Wounds and Injuries, 290. — Ecchymosis, 291. — Furuncle, 292. — Cancer, 293. — Excrescences, 294. — Adhesions of Lids, 294. — Encysted Tumors, 295. — Liable to refill if merely punctured, 297. — Albuminous Tumor, 298. — Fibrous Cysts, 298. — Vitiligo, 299. — Diseases of the Meibomian Glands and Ciliary Bulbs, 301. — Hordeolum, 299. — Stye, 299. — Trichiasis,

306. — Inversion of Eyelashes, 306. — Lice on Borders of Lid,

307. — Entropium; or Inversion of Lid, 307. — Ectropium; or Eversion of Lid, 309.

DISEASES OF THE EYE.

We shall derive the greatest advantage, in our study of the pathology of the eye, from such a classification of its diseases as may not only aid us in forming a prompt diagnosis, but assist in determining, at once, the general plan of treatment to be adopted. The most simple and rational arrangement, and one which includes a very large proportion of the numerous diseases of the eye, is that which ranks them, as far as may be, according to the structure which they primarily affect. A further subdivision is required, to designate those peculiar phases of disease denoting the existence of any constitutional condition or other circumstance capable of modifying the course of the malady or its results.

Many of the inflammatory as well as other affections of the eye are distinctly limited, at the outset, to certain of its tissues, — as the iris or the conjunctiva, — and may disappear without involving contiguous parts ; but even these, if left to themselves, tend to produce new conditions, affecting l other structures, and complicating or even masking the original disease. As an instance of this latter tendency, we may refer to the effect produced upon the cornea by long-continued friction of granulated lids upon its surface. For a considerable time, especially if the granulations are flabby rather than hard, the cornea continues clear ; but at length vessels become developed upon its surface, it loses its transparency, and, if the original disease remain unchecked, it becomes ulcerated, and perforation very probably ensues. When these changes have occurred, attended, perhaps, with much circum-orbital pain, serving still further to disguise the case, it is difficult for an inexperienced observer to recognize, as the cause of all this mischief, a condition of the mucous membrane lining the upper lid, towards which, if he hope for success, his remedial measures must be primarily and almost solely directed.

In order to unmask these complications, and discover the true features they conceal, — or, when they have themselves become, de facto, new diseases, to determine where and how to direct his treatment, — it is essential that the observer should accustom himself to close and careful examination of the eye, overlooking no morbid change, however apparently trivial. This being of so much consequence, I shall endeavor to point out the mode of making an accurate and methodical examination, that the student may have a guide as to what he should look for, and how he is to find it.

METHOD OF EXAMINING THE EYE.

Chapter I. Method Of Examining The Eye

So far as it goes, information obtained by the physician's own senses is of more value than that derived from the patient. As a general rule, therefore, a personal inspection should precede any inquiries as to the history or symptoms of the case. Thus relying on his own observation, the physician learns to note every deviation from a normal condition, — he avoids, in a measure, the chance of being misled by preconceived theory in the mind of his patient, — and he may often gain, at once, the patient's confidence, by showing, in his first question or remark, that he thoroughly comprehends the disease.

The examination of the patient may commence from the moment he enters the room. The skilful observer will distinguish, in his very bearing, the patient with cataract, who, with shaded eyes, appears as if searching his way, from him who has the bold gait and wandering eyeballs marking the loss of all perception of light. The half-closed lids of the short-sighted, the spasmodic contraction attendant on intolerance of light, the deviation from harmonious action in the eyes of those affected with strabismus, may all be observed at a glance.

The patient should be seated near a window, with the light falling obliquely on his eye. For examinations requiring much delicacy, a window having a north aspect is best.

The appendages of the eye, the brow and lids, should receive an instant's attention before we turn to the globe itself. Recent wounds or contusions of the eyebrows, or the cicatrices resulting from former injury, are worthy of note, as such accidents now and then, through the supi'a-orbital branch of the fifth pair, seriously affect the poAver of vision.

In the lids, we should observe if there is any loss of the natural freedom of motion, whether from muscular paralysis, or from thickening of their structure, or from photophobia. We should note any inversion or eversion of their edges, or the existence of wounds, ecchymosis, oedema or tumors. The tarsal borders may be thickened ; or covered more or less with crusts, indicating disease of the Meibomian glands ; or infested with pediculi. The absence of a portion of the eyelashes, or their misdirection, constitutes another important change. In cases where the cilia are thus misdirected, growing towards the eyeball, they are often so pale, from constant immersion in the secretions of the eye, that it is difficult to detect them, and they may be best discovered by the fact that the tears are drawn slightly around them by simple attraction.

Any alteration of the position of the globe, or other evidence of tumors in the orbit, should be at once noted.

All the appendages of the eye having been scrutinized at a rapid glance, we turn our attention to the globe itself. Its anterior surface should be carefully passed in review, to detect the presence of any foreign body, ulceration of the cornea, vascularity or cloudiness resulting from friction of granulated lids, or lingering traces of former disease of the cornea ; or any abnormal conditions of the conjunctiva, such as the olive stain produced by long-continued applications of solutions of the nitrate of silver, chemosis, small papula?, pterygium, or any increase of vascularity. If abnormal vascularity of the eye exists, we are to observe its character and seat, whether it affects the superficial and inosculating conjunctival vessels, or the radiating zone of those of the sclerotica, and whether accompanied or not by augmented secretion. We should also detect any alteration of the form of the globe, from conicity of the cornea, staphyloma, hydrophthalmia, or atrophy.

If there is reason to suppose that an extraneous substance has become lodged under the lids, or to suspect the existence of granulations, the lids should next be everted. In nine cases in ten, a foreign body which may have intruded is found at the centre and near the edge of the upper lid.

6 DISEASES OE THE EYE.

As we proceed to explore the internal parts of the eye, the clearness or haziness of the field of the pupil, its size, irregularities in its outline, or any unusual appearances in the iris, are to be noted. The contractility of the pupils must be tested in each eye separately. To do this the fingers of one hand are placed upon the brow and the thumb upon the upper lid of one eye, the other hand being similarly placed as regards the other; and the lid of one eye is to be raised by the thumb, without pressure, while the other is kept closed. Unless this is done, we may be deceived, as the light falling on one eye causes sympathetic contraction of the other pupil, though that eye may have lost all sensibility to light. This alternate closing and opening of the eyes also aids us in detecting cataract or other chancres behind the iris ; as, by covering the eye for a moment, we obtain such dilatation of the pupil as permits of a quick glance over a larger field. By pressure of the thumb upon the globe, we are also enabled to judge as to any increase or lessening of the normal degree of hardness, indicating tension on the one hand or on the other commencing atrophy of the eye.

Should it be desired to dilate the pupil for the purpose of obtaining a better view of the deep-seated parts, this may best be done by touching the inner surface of the lower lid with a small camel's-hair pencil dipped in a solution of the sulpliate of atropia, of about five grains to the ounce. This application will be painless, and produces considerable dilatation in tifteen or twenty minutes. The lens, the vitreous mass, and the whole of the posterior portion of the interior of the globe, may now be examined to great advantage. Should the physician be unprovided with atropia, the object may be accomplished by using the fresh juice, or a solution of the extract of belladonna or stramonium, which may be smeared upon the eyebrows and lids.

Various pathological changes may be discerned in the deeper parts of the eye, especially after having dilated the pupil, without the aid of the ophthalmoscope,— as, for instance, opacities of the lens, constituting cataract; or those more profoundly situated, in the vitreous body ; or the formation of purulent collections or commencement of cancerous disease at the posterior part of the globe. With the ophthalmoscope, we may detect the minutest differences of vascularity or exceedingly delicate changes of structure in the retina itself, as well as the incipient stages of the above-named affections.

If we are satisfied that the lining of the lids is in a healthy condition, the upper lid need not be everted. But in very many cases, including a large share of those where the conjunctiva is affected, the source of mischief is to be found in this very situation. Almost invariably the upper is much more diseased than the lower lid. This is principally due to its anatomical configuration, — the upper lid being broader than the lower, — and to its position, rendering its vessels more liable to become and remain engorged, from the influence of gravitation ; whereas the circulation in the lower lid more readily recovers from any temporary congestion. As in these cases eversion of the lid must be performed, perhaps daily, for a considerable time, for the purpose of applying remedies directly to the affected parts, it is of great consequence to the patient's comfort and the surgeon's success that adroitness and delicacy in executing this little manoeuvre should be acquired. The eyelashes and edge of the lid are to be taken hold of with the thumb and finger of the left hand, and drawn gently forward and then upward, while at the same moment pressure is made against the lid, at about the upper edge of the tarsal cartilage, with a probe, a small pencil, or some similar object, held in the other hand, — the upper edge of the cartilage being thus tilted backward while the lower edge is brought forward. The patient is to look down, thus making the reversal of the lid more easy.

METHOD OF EXAMINATION IX CHILDREN.

With small children, especially those suffering from photophobia, or who have been long diseased, we must use a different method in our examination. It is important to avoid terrifying them, as any future inspections, or even the application of necessary remedies, are thus rendered more difficult ; and, moreover, we can often obtain a better view by patience and stratagem than we can by force. By calling the child's attention to something else, and not appearing to care for the eye, we may often see it to good advantage ; and, if we can gain but a momentary glance in cases of photophobia, this may suffice to assure us that the cornea is not seriously threatened, which, for the moment, is all we need to know. But if the child is unwilling or unable to allow us this assuring glance, — or where, in other cases, the swollen state of the lids prevents their being easily raised, — we must often feel compelled, at least at a first examination, to ascertain the exact condition of things by the employment of gentle force. The child should be held on the knees of another person, his feet turned from the surgeon, who sits at right angles to the individual holding the child. His head should then be lowered between the surgeon's knees and firmly grasped by them, and, his hands being held by the attendant, he can make no resistance. Both hands of the surgeon are free, and he can depress the lower lid with one hand, while with the other he raises the upper lid. Should the resistance offered by the orbicularis muscle be too strong, or the lid be greatly swollen, it may be necessary to use an elevator to raise the upper lid, so as to obtain the requisite view of the cornea, l *

Any remedial measures may be applied, if necessary, while the child is in this position.

VARIETIES OF INJECTION AS A MEANS OF DIAGNOSIS.

I have alluded to the distinct characters of the injection of the external vessels, and those more intimately connected with the internal parts. The vessels of the conjunctiva run tortuously upon its surface, inosculating in all directions, and may be readily moved over the surface of the sclerotica by friction exercised through the eyelid. They have a bright scarlet color, and are largest at the point where the conjunctiva is reflected from the lid upon the globe. Even though the injection should be sufficient almost to hide the sclerotica, it may still be distinguished by these features. Injection of the sclerotica is characterized by the presence of minute vessels, largest next to the margin of the cornea, and tapering to an invisible fineness as they radiate upon the globe. They form a distinct circum-corneal zone, of a purplish or lake tint, and cannot be displaced by friction. They are evidently deeper seated than the conjunctival vessels.

DIFFERENCES IN THE SECRETIONS.

A similar marked difference is exhibited in the nature of the secretions. Those poured out by an inflamed conjunctiva have a more or less viscid mucous or purulent consistence ; while those which flow when the internal parts are implicated, or when ulceration of the cornea exists, seem to be derived, to a large extent, from the lachrymal gland, and have the character of acrid tears.

DIFFERENCES IN PAIN COMPLAINED OF.

The kind of pain complained of by the patient is also very characteristic of the diseases it accompanies. In conjunctivitis, the sensation is one of smarting, or as if sand or sticks were in the eye, and is generally evidently superficial ; while in inflammations of internal parts of the eye, and sometimes in cases of ulceration of the cornea, the pain has an aching character, extends deeply through the organ, and frequently affects also the circum-orbital branches of the fifth pair.

The difference in the characteristics of affections as indicated by these three symptoms — the injection, the secretion, and the- pain — should never be forgotten, as a due appreciation of these is of the greatest assistance in making a diagnosis, and of the greatest value as regards treatment. We may feel little anxiety and give a favorable prognosis in a case of severe conjunctivitis, where the amount of redness renders the disease formidable to the eyes of the patient's friends ; whilst we watch with far more solicitude an eye which seems to others only slightly affected, but where we find deep-seated pain and development of radiating vessels, denoting, to our experienced estimation of their value, implication of important internal parts.

Chapter II. Use Of The Ophthalmoscope

The ophthalmoscope is now so well known that it seems scarcely to require description in these pages. Yet, as its invention is still recent, a few words as to its principles of construction and application may not be misplaced.

Previous to the success of Helmholz in devising means for a satisfactory illumination of the deeper parts of the eye, nearly the whole of that portion lying behind the crystalline lens was veiled to our observation ; it being difficult to place our own eyes in a position to receive rays which are reflected from another retina in the direction in which they reach it, — any attempt to do so intercepting the luminous rays themselves. His invention has made a large addition to our means of diagnosis of the deep-seated diseases of the eye.