The pathology and treatment of pulmonary tuberculosis; and on the local medication of pharyngeal and laryngeal diseases frequently mistaken for, or associated with, phthisis

Front matter

YALE MEDICAL LIBRARY

HISTORICAL LIBRARY

THK

Dedication

If, in following out the recommendation thus given, I have been enabled to collect facts which prove that a cure may occasionally take place, although phthisis has existed to a very great extent ; and if, from a consideration of these facts, I have been enabled to approximate towards, if not completely to arrive at, a knowledge of the circumstances which produce a permanent arrestment of the malady, you will perhaps excuse my dedicating this work to you — a liberty to which I am impelled as much by the kindness I have experienced at your hands, as by the distinguished reputation which you have achieved in medicine.

With the utmost respect and regard,

I remain, my dear Sir,

Preface

In the years 1839-40 the Author found a remedy administered in the hospitals of Germany in cases of Pulmonary Tuberculosis, which had never been employed in his own country for that disease, although it had been successfully used there in Rheumatism. This was Cod-liver Oil. He could not fail to be struck with the marked benefits which resulted from its employment in patients who, had they been treated in British hospitals, would certainly have died. In 1841, therefore, he published a Monograph, giving an account of what was then known concerning that substance, and recommended it to his countrymen, from theoretical and practical considerations, as a valuable remedy in Phthisis Pulmonalis.

For five years (1843-1848), the Author held the position of Pathologist to the Royal Infirmary of this city, during which period he performed and recorded the results of upwards of 2000 post-mortem examinations. Gradually one great fact became impressed upon his mind, viz., that all organic diseases occasionally presented a tendency to spon-

6 PREFACE.

taheous cure. He was repeatedly meeting with instances where, although death was occasioned by disease in one organ, there were others which presented traces of previously existing lesions which in some way had healed. In no organs were such appearances more common than in the lungs, and of no disease was evidence of a spontaneous cure more frequent than of Pulmonary Tuberculosis.

Although it was generally considered by the profession that no remedy and no plan of treatment yet proposed could be depended on in cases of consumption, it was obvious to the Author that if the process employed by nature could be discovered, and then imitated by art, we might ultimately arrive at the true principle of cure. Whenever, therefore, decided and unmistakeable evidence of a spontaneous cure came before him, he carefully studied the circumstances which preceded it; and connecting these with the numerous observations which were simultaneously going on, as to the good effects of Cod-liver Oil, he was gradually led to the rules of treatment which are developed in the following pages. These he has tested on a large scale in hospital and private practice. They have also been extensively tried by others who have followed his suggestions, so that he can now confidently recommend them to his j>rofessional brethren.

It may happen, however, that the practical rules and the principles on which they are founded are no longer new to some who may read the following pages. This will be accounted for if it be remembered that during the last twelve years the Author has published various papers in connection with Tubercle and Pulmonary Tuberculosis, the substance of

PREFACE. 7

which is embodied in the present work. 1 For the last eleven years also he has been constantly engaged in giving lectures, both on the Theory and Practice of Medicine, systematically and clinically, and has naturally communicated to his pupils the various facts and views now set forth, as they were gradually arrived at or reached maturity in his own mind. Further, it may be observed in some places that the language and ideas are similar to those long since published in certain Reviews, which have appeared in the " Monthly Journal of Medical Science," and whenever these are identical, it

1 The Author is not disposed to enter into controversy with regard to a mere question of priority ; but with the object of regulating any discussion on this point, should it arise, he appends a list of his contributions to the pathology and treatment of tuberculosis, with the dates of their publication.

1 . Treatise on the Oleum Jecoris Aselli or Cod-liver Oil, as a Thera-

peutic Agent in certain forms of Gout, Rheumatism, and Scrofula, with Cases. London and Edinburgh. 1 vol. 8vo. 1841.

2. Description of a Cryptogamic Plant found Growing in the Sputa

and Lungs of a Man who laboured under Pneumothorax. — "Transactions of the Royal Society of Edinburgh." 1842.

3. On the frequent Spontaneous Cure of Pulmonary Consumption, and

the indications furnished by Patholoyy for its Rational Treatment. — "Edinburgh Medical and Surgical Journal." 1845.

4. On the Minute Structure and Chemical Composition of Tubercular

Deposits. 6 woodcuts. — " Northern Journal of Medicine" 1846.

5. On the Elementary Forms of Disease. Woodcuts. — "Monthly

Journal of Medical Science." 1846.

8 PREFACE.

may be assumed with truth that lie is the writer of those Reviews.

In 1849, Dr C. T. B. Williams, of London, published a paper on the treatment of Phthisis Pulmonalis by Cod-liver Oil, in which he confirmed all that the Author had stated eight years previously as to the therapeutic effects of that remedy. Dr Williams also adopted the molecular theory of its action which the Author published in November 1847. Unfortunately, in adopting his theory as well as practice, Dr Williams seems to have imagined that he had arrived atsome-

6. On the Structural Relation of Oil and Albumen in the Animal Eco-

nomy, etc. — " Read to the Royal Society of Edinburgh," 19th April 1847 ; " Proceedings of the Royal Society of Edinburgh, 1 S46-7 ;" and " Monthly Journal of Medical Science," September 1847.

7. Appendix to the Treatise on the Oleum Jecoris Ascelli. Svo. No-

vember 1847.

8. On Cancerous and Cancroid Growths. 1 vol. Svo. Numerous

Woodcuts. Edinburgh. 1849. See pp. 195-7 and pp. 204-6.

9. On the Course of Tubercle in the Lungs. — " Monthly Journal of

Medical Science." 1849.

10. On Simple Tubercular and Cancerous Exudations — their Pathology

and General Treatment. — " Monthly Journal of Medical Science," February 1850.

11. Ore the Treatment of Phthisis Pulmonalis. 2 Coloured Plates.

" Monthly Journal of Medical Science." 1850.

12. Report on the Cases of Pulmonary Diseases treated in the Clinical

Wards of the Royal Infirmary, during the latter half of the Summer Session 1851. — " Monthly Journal of Medical Science/' December, January, and February. Nos. 1851-52.

13. Illustrations of Laryngeal and Pharyngeal Diseases, which arc

frequently mistaken for, or associated with, Phthisis Pulmonalis. — "Monthly Journal of Medical Science. - ' December 1852.

PREFACE. i>

thing new — a conclusion which, as it has been very ably dealt with by a critic in the " Dublin Quarterly Journal of Medical Science" for May 1850, demands no further notice. There can be no doubt, however, that Dr Williams' confirmation of the Author's experience (although tardy), still further supported by an able Report of the Medical Officers of the Brompton Consumptive Hospital in 1851, and the concurrent testimony of several Hospital Physicians, tended to extend the confidence of the profession in its use, which has since become as general in England as it had long previously been in Scotland.

Any well-informed medical practitioner who looks back on the treatment of Phthisis as it existed ten years ago, and compares it with the practice recommended in this work, must come to the conclusion that the one is essentially different from the other. The Author has attempted to show, 1st, That tubercular diseases will heal of themselves, if the faulty nutrition of the system can be removed ; 2dly, That with this object our efforts should be directed to the digestive rather than to the respiratory system ; and 3dly, That the kind of abnormal nutrition which exists is dependent on increased assimilation of the albuminous, and diminished assimilation of the fatty portions of the food. Hence he recommends that the general plan of treatment should be to cause the reception of the deficient elements of nutrition, and is therefore not tonic or stimulating, but analeptic (from avaXanfiava, to restore). With regard to the symptomatology, morbid anatomy, and diagnosis of Pulmonary Tuberculosis, he has nothing to add to the many masterly works which treat of those parts of the subject, and

10 PREFACE.

consequently he has not entered into them farther than w;is necessary to evolve the principles on which he considers a correct treatment should be based. But if he has been fortunate enough to show that such treatment is founded on a true pathology, and that a class of diseases which destroys one sixth of the population in this country may in any way be alleviated, he leaves to the candour of his medical brethren the question of how far he has been instrumental in effecting it.

JOHN HUGHES BENNETT.

Contents

Pago

Dedication, ....... 3

Preface, ..... . o

Section I. — Histology of Tubercle, . . 14 II.— The Nature of Tubercle, . . .22

III — Natural Progress of Tubercular Exudation — Its Tendency to Ulceration — Its Modes of Arrestment, . . . .31

Imperfect Digestion and Assimilation the chief

cause of Pulmonary Tuberculosis, . 52

Importance of a correct Diagnosis illustrated, . 55

CHAPTER II. General Treatment of Pulmonary Tuberculosis, . . 60

First Indication — To improve the faulty nutrition, which is

the cause of the exudation assuming a tubercular character, 62 Indication for, and Modes of Administering, Fatty

Substances, . . . . .64

Second Indication — To favour Absorption of the Exudations already poured out, and subdue the Symptomatic Fever produced, . . 67

Bleeding Contra-indicated, . . .68

Third Indication — To prevent the recurrence of fresh Exudations by careful attention to Hygienic Regulations, . 72 Climate, .... 73 Exercise, . 77 Diet, . 78

12 CONTENTS.

CHAPTER III. Page

Cough and Expectoration, . . 85

Loss of Appetite and Anorexia, . 86

Nausea and Vomiting, ... 86

Diarrhoea, ... 87

Haemoptysis, . . .87

Sweating, ... . .88

Febrile Symptoms, . 89 Debility, . .... 90

Despondency and Anxiety, ... .91

Illustrative Cases, . . . . 107

Chapter IV

Observations on the Use of Local Applications to the Pharyngeal and Laryngeal Diseases which are frequently MISTAKEN FOR, OR ASSOCIATED WITH, PULMONARY

Tuberculosis, ....... 126

Illustrative Cases, . . . . 126

Mode of Employing Local Remedies, , . 138

ON PULMONARY TUBERCULOSIS.

Chapter I. Pathology Of Pulmonary Tuberculosis

It has been noticed by many observing physicians, and especially by Sir James Clarke, that phthisis pulmonalis is ushered in with a bad and capricious appetite, a furred or morbidly clean tongue, unusual acidity of the stomach and alimentary canal, anorexia, constipation alternating with diarrhaja, and a variety of symptoms denominated dyspeptic, or referable to a deranged state of the prima? vias. Moreover, it can scarcely be denied that, in the great majority of cases, these are the symptoms which accompany phthisis throughout its progress, becoming more and more violent towards its termination. Now, as the nutritive properties of the blood are entirely dependent on a proper assimilation of food, and as this assimilation must be interfered with in the morbid conditions of the alimentary canal, the continuance of such conditions necessarily induces an impoverished state of that fluid, and imperfect growth of the tissues. When, under such circumstances, exudations of the liquor sanguinis occur, they are very liable to assume the form of tubercles, and if they are poured into the lungs, there are then produced those changes and that condition which have been denominated by the German pathologists pulmonary tuberculosis.

The term tubercle is of Latin derivation, and literally implies a little swelling. In this sense it is still used by dermatologists, and serves to distinguish a class of skin diseases. The same name was unfortunately applied to the rounded

14 HISTOLOGY OF TDBERCLE.

masses so frequently found in the lungs or other organs. It has also been employed to characterise the same substance when infiltrated in masses, or under circumstances where its original signification cannot apply. At present, tubercle is generally considered to be a peculiar morbid deposit, sometimes grey, but more frequently of a yellowish colour, varying in size, form, and consistence, which sooner or later undergoes a process of softening.

This definition of tubercle is very vague, and may be applied to various kinds of exudation which materially differ from each other. Indeed every morbid anatomist must frequently have experienced much difficulty in endeavouring to determine by the naked sight whether a certain morbid deposit be or be not tubercle. With a view to establishing a correct pathology therefore, our first efforts must be directed to determine what tubercle really is ; how it can be accurately separated from the ordinary products of inflammation on the one hand, and from malignant or other morbid growths on the other. To arrive at these points we must inquire into the minute structure and chemical constitution of this substance.

SECTION I.

Histology of Tubercle.

Tubercle has been spoken of as presenting a miliary, infiltrated, or encysted form ; but these distinctions have no reference to structure, but merely to the extent and age of the exudation. It generally presents a yellowish or dirty white colour, and varies in consistence from that of a substance resembling tough cheese to that of cream. Sometimes it is soft at one place and indurated at another. On section, when tough, it presents a smooth or waxy, and when soft, a slightly granular, surface. On pressure it is friable, and may break down into a pulpy matter, but never yields a milky juice.

A small fragment of tolerably firm miliary tubercle, squeezed between glasses with a drop of water, and examined under a magnifying power of 250 diameters linear, presents a number of irregular shaped bodies, approaching a round, oval, or tri-

HISTOLOGY OF TUBERCLE.

Fig. 1.

lb 0; "F

Tubercle ft w corpuscles

Fig. 2.

angular form, varying in their longest diameters from the ziyoff t° tne Wo o °f an i nc h. These are the so-called tubercle corpuscles. They are composed of a distinct wall, containing generally three or more granules, without any distinct nucleus, and are mixed with numerous granules and molecules, varying in size from a point scarcely measurable, to the ^oVjo of an inch in diameter (Fig. 1, a). If we add to these bodies a drop of weak acetic acid, all the corpuscles become more transparent, but are otherwise unchanged, l£h m s th me P afte™h" m addi and many of the granules disappear, as in tion of acetic acid. Fig. 1 (b). (Ether and alcohol produce little change. Ammonia partially dissolves the corpuscles, and renders them capable of being easily broken down. They are immediately and completely dissolved in a solution of potash.

Again, if we simply squeeze a portion of soft yellow tubercle between glasses, and examine it with a like magnifying power, we shall see similar corpuscles, mixed with numerous molecules and granules, as in Fig. 2. Sometimes softened tubercle seems partially or wholly composed of a granular matter.

At others, we only observe it to be molecular, the molecules being exceedingly minute. In some forms of tubercle, the corpuscles are much larger and rounder than they are represented in Fig. 2, still, however, preserving their peculiar character, as in Fig. 3.

In this manner, they approach in form to the corpuscles observed in scrofulous pus.

m

Tubercle corpuscles, granules, and molecules, from a soft tubercular mass in the lung. 250 diameters linear.

Fig. 3.

Fig. 4 mm

, Tubercle corpuscles from a mesenteric Fig. 4. Scrofulous pus from a lymphatic gland. 250 diameters linear.

HISTOLOGY OF TUBERCLE.

The grey semi-transparent granulation is of semi-cartilaginous hardness, and presents to the eye a very different appearance from ordinary tubercle.

On making a thin section

Fig. 5.

Fig 6.

Fig. 5. Section of a grey granulation in the lung after the addition of acetic acid, showing the pulmonary air vesicles filled with tubercle corpuscles. 250 diam. linear.

of it, however, it will be found to be composed of similar elements, although more transparent and not so well defined. The addition of acetic acid, by rendering the fibrous tissue more transparent, and dissolving the granules, will permit the same corpuscles to be seen in it as are represented in Fig. 1.

When tubercle presents the cretaceous or calcareous transformation in any degree, the different elements we have described become mixed up with hard gritty particles of earthy salts. These are of irregular form and size, and are larger and numerous in proportion as the tubercle is more and more calcareous. Crystals of cholestrine may also frequently be seen in cretaceous concretions (Fig. 6). When tubercle is converted into a mass of stony hardness, a thin section presents a granular appearance, made up of a congeries of minute earthy particles, without any distinct form

Fig. 6. Fragments of phosphate of lime, crystals of cholestrine, and tubercle corpuscles, from a cretaceous muss in the lungs.

We frequently find tubercle conjoined with more or less pigmentary matter. This usually appears under the microscope in the form of irregular black masses (Fig. 7, a), m g . i. which are composed of exceedingly ™ -*••.••■ minute molecules (b). These mo- ■§^^^jf$& t lecules may be occasionally seen in- $c£§Wl^$ ^ filtrated into many of the tissues, .•8'Vl^l^SaVQf and among morbid deposits, especially 1! t»5|^<si$* Kf tubercle. They often surround the *^*5-rV a ' minute tubercles deposited on the

surface of the peritoneum, as in Fig. ^L^SX^^T 7. Their occurrence in consider- ^{^'^.fffiT: able masses round chronic tubercle ^^ZZ^^Z^r in the lung or bronchial glands, matter - ?6 ° di!imet " s Unear - is almost uniform, giving a black or bluish tinge to the tissues. Indeed, it may be said that the older the tubercle, the greater is the amount of pigmentary matter surrounding it. In the lungs and bronchial glands, however, the black pigment, although it resembles that observed in the peritoneum morphologically, differs from it chemically. In the former case, it is pure charcoal, and indestructible by all chemical reagents ; whereas, in the latter, the colouring matter disappears under the action of mineral acids, and an immersion for some time in alcohol. A portion of intestine sprinkled over externally with miliary tubercles, surrounded by a black ring, one of which is represented magnified 250 diameters (Fig. 7), was put up by me in alcohol as a preparation, and in three weeks the black pigment had entirely disappeared.

From what has preceded, it must be evident that tubercle presents different appearances, according as it is hard or soft, cretaceous or calcareous. When recent and hard, the corpuscles are crowded together, and the granules accompanying them are comparatively few in number. When soft, the number of granules is much increased, and the corpuscles are easily separated. Lebert 1 is of opinion that at first the cor-

1 Physiologie Pathologique, p. 527, et seq.

puseles are kept together by an intermediate substance, which afterwards softens. We can only regard this interglobular substance as the blastema in which the corpuscles are formed. The softening, then, is more probably owing to the development and breaking down of the latter, similar to what we observe in inflammatory exudations generally.

Gulliver 1 and Vogel 2 agree in saying, that at an early period, mor.e especially when in a miliary form, nucleated cells may be observed in tubercular matter. This is denied by Lebert, and I must confess that I have never been able to discover nuclei in the corpuscles of tubercle. They appear to me to be nuclei themselves, which are formed slowly, and have no tendency to produce cells, before they break down into a molecular matter. Hence no danger is to be apprehended from the spread of tubercle itself by an inherent power of growth, and if fresh deposits could be prevented, the tendency of this substance to disintegration, is highly favourable to its absorption. Schroeder Van der Kolk also supposes them to be nuclei ;

Fig 8. Fig. 9.

pillltStp.

kifftit

Fig S. Structure of the central portion of a tubercular mass, embedded in the cerebellum. Fi£. 9. Structure of the external portion of the same mass, where it was in contact with softened cerebellar substance. 250 diameters linear.

but considers that they result from the disintegration of epithelial cells in the ultimate bronchi and air-vesicles — a view which seems to me negatived by the fact that they occur in textures destitiite of epithelium, as in the substance of the brain (Figs. 8 and 9).

HISTOLOGY OF TUBERCLE.

Numerous instances occur in which it is utterly impossible to distinguish tubercle from fibrinous exudations on the one hand, or cancerous growths on the other, except by paying attention to the minute structure previously described. I have often been deceived in endeavouring to determine this by naked sight, and found on a microscopic examination, that so-called tubercular masses were composed of filaments more or less mixed up with plastic or granular corpuscles. Again, not unfrequently tubercle has been mistaken for cancer, or the latter for the former. If, then, we ai'e asked to determine what is positively tubercle, as distinguished from all other morbid products, we must answer, that deposition which is composed of the peculiar corpuscles and granules described and figured in the preceding pages. From pus corpuscles they are readily distinguished by the action of acetic acid, which in them causes no granular nucleus to appear. From plastic corpuscles they may be separated by their irregular form, smaller size, and the absence of primitive filaments. With the granular corpuscle they can scarcely ever be confounded, on account of its large size, brownish or blackish colour, and nucleated or granular structure. The cells of cancer are large, transparent, and distinctly nucleated, and consequently easily distinguished from the small, non-nucleated corpuscles of tubercle. The general characters of these different corpuscles will be gathered from a glance at the accompanying figures.

Fig. n.

Fig 12.

Fig. 10. Tubercle corpuscles from the lunp. Fig. 11. Pus corpuscles. One shows the double granular nucleus after the addition of acetic acid. Fig. 12. Plastic or pyoid corpuscles. Fig. 13. Granular corpuscles from cerebral softening. Fig. 14. Cancer cells from the uterus. 250 diameters linear.

The only other structure likely to be confounded with tubercle is the reticulum of cancer, which not only presents a

20 CHEMISTRY OF TUBERCLE.

yellowish appearance closely resembling it, but is composed oi

nuclei and molecular matter, resulting from the disintegration

of cancer cells. But, as this reticulum is

always associated with cancerous formation,

it may at once be distinguished by the cell ^a&ir^jk

elements which accompany it. It should ilffj*lS^||

OT further be noticed that every form of exuda-

tion, at a certain period, presents a molecular "'^•^■0^'

and granular structure throughout, and that corpuscirs, etc..

then it becomes impossible to determine its t™ce^ ^et 25o'di^m C . ,

nature, unless it be associated with the more

characteristic elements distinctive of the simple, tubercular,

or cancerous exudations.

As regards chemical composition, Dr Abercrombie 1 showed that a mass of tubercle, on being plunged into boiling water, contracted and became more dense and firm, when it presented all the characters of coagulated albumen. This was well observed in the mesenteric glands, which, when only slightly affected, lost a considerable amount of their weight. This loss became less and less as the tubercular deposition increased, until at length the whole gland appeared to be converted into solid coagulated albumen, and scarcely lost any of its weight by boiling.

Dr Abercrombie observes, " the deposition of albumen, therefore, in these glands, appears to be a process of disease. In the early stages of the disease it seems to be deposited in a soft state, and to be involved in the structure of the gland ; the gland, in other respects, being vascular and organised, and probably capable of performing its functions. It. is in this state that we see the albumen coagulated, when the gland is plunged into boiling water, producing so immediate and remarkable a change in its appearance and texture. As the disease advances, the proportion of albumen seems to increase, while, at the same time, it assumes a more concrete state, and the mass in general becomes less vascular and less organised.

1 Medico-Chirurgical Transactions of Edinburgh, vol. i.. p. 887.

CHEMISTRY OF TUBERCLE. 21

In the last stage, the vascular structure of the gland seems more and more to disappear, until it passes into a mass presenting the properties of coagulated albumen, with little or no organisation"

Tubercle has farther been made the subject of special analysis by Thenard, 1 Hecht, 2 Lassaigne, 3 Preuss, 4 Gueterboeck, 5 Wood, 6 Simon, 7 Scherer, 8 Felix Boudet, 9 Wright, 10 and especially by Dr Glover of Newcastle, 11 from whose various analyses, the following conclusions may be drawn : —

1st, That tubercle consists of an animal matter, mixed with certain earthy salts.

2d, That the relative proportion of these varies in different specimens of tubercle. That animal matter is most abundant in recent and earthy salts in chronic tubercle.

3d, That the animal matter certainly contains a large amount of albumen. Some chemists have also detected caseine, the existence of which is probable ; others gelatine, the presence of which is more doubtful. The statement of Gueterboeck, that it contains a peculiar animal matter (phymatine), has not been confirmed by other analysts. Fibrin and fat exist in small but variable proportion, as a constituent of tubercle.

4th, The earthy salts are principally composed of the insoluble phosj)hate and carbonate of lime, with a small proportion of the soluble salts of soda. The statement of Boudet, that cretaceous concretions are principally formed of the latter,

1 Andral. Precis d'Anatomique Pathologique, t. i., p. 417. 1829.

2 Traite d'Anatomie Pathologique, 1829, t. i., p. 378.

" De pure et granulatione. Berol, 1837.

7 Animal Chemistry, 1842. Trans, by Day, 1846, vol. ii., p. 478.

10 Medical Times, vol. ii., pp. 418, 419.

11 Pathology and Treatment of Scrofula, 1846, p. 54, et seq.

is directly opposed by other chemists, and is quite incompatible with their long persistence in the body.

5th, That very little difference in ultimate composition has yet been detected between recent tubercle, and other so-called compounds of protein.

SECTION II. The Nature of Tubercle

If, from the histological facts previously stated, we seek to deduce the nature of tubercle, it can scarcely be doubted that it is an exudation of the liquor sanguinis, but one which presents marked differences from the simple or inflammatory exudation on the one hand, and the cancerous exudation on the other. Thus : — -

We observe, in a simple or inflammatory exudation, that it may occur at all epochs in life ; that it may attack all tissues, and most commonly those which are very vascular; that it may be poured out in large or small quantities ; and that it may occur with greater or less rapidity — hence the terms acute and chronic. We further observe, that the acute exudations are generally attended with symptoms of a peculiar character (inflammatory), and have a great tendency to cell or temporary formations, which rapidly break down, are absorbed, and excreted by the emunctories : that the chronic exudations, on the other hand, have a tendency to fibrous or permanent formations, producing adhesions, strictures, hypertrophies, etc.

We observe, in a cancerous exudation, that it occurs for the most part in persons of adult or advanced life ; that it may also occur in every tissue, but is by far most common in glandular or fatty organs, such as the liver or female mamma, and is very apt to attack the lymphatic glands secondarily ; that its progress, although sometimes slow when very fibrous, becomes rapid when corpuscles abound in it ; that there is a great tendency to the formation of the most perfect forms of cell life, which have the power of self-development, and thereby of spreading to neighbouring tissues ; and lastly, that -when, by pressure, ulceration is produced on free surfaces, it bursts through these in exuberant fungoid excrescences.

We observe, in a tubercular exudation, that it occurs for the most part in young subjects, between the periods of dentition and of adult age ; that it may also occur in all tissues, but is by far most common primarily in the lymphatic glands, and afterwards in fibrous or albuminous textures, as the lungs and serous surfaces ; that its progress is generally exceedingly slow ; that there is no disposition to the formation of perfect cell-formation, but rather to abortive corpuscles, which form slowly, and slowly break down ; that there is little tendency to absorption, but great liability to disintegration and ulceration ; and finally, that the local changes are almost always preceded by derangement of the prima? vise, and a group of symptoms known under the name of dyspepsia.

Taking, then, the products of simple inflammation (say pus) as a standard, we cannot fail to remark, that whilst the cell development of tubercle is below, that of cancer is above, this standard. Of the three kinds of exudation, tubercle is the lowest, and cancer the highest, in the scale.

On what this difference in the formative power of the exudation depends, we are ignorant, but every kind of reasoning must lead us to the conclusion, that these different changes and effects depend, not upon the vascular system, which is the mere apparatus for the production of exudation ; not upon the nervous system, which conducts impressions to and from this apparatus ; and not on the texture, which is the seat of the exudation, as that varies, whilst the cancerous or tubercular formation is the same — but on the inherent composition or constitution of the exudation itself. On this point most pathologists are agreed, and hence the supposed existence of various kinds of dyscrasiae, originating in the blood, which, it is imagined, explain the different results produced. But here pathologists pause— having once traced these lesions back to the blood, they are content ; and they have not sufficiently taken into consideration, that the blood itself is dependent for