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FURTHER RESEARCHES ON TUBERCLE, ETC. 13

But in a scrofulous subject, the cacoplastic or degenerating tendency may have been already manifest in enlargement and caseation of the lymphatic glands, or in the spontaneous formation of indolent abscesses or ulcers; and in such a subject, any inflammation of the lung, however acute, may end in consumptive destruction, through the imperfectly organised (aplastic), and therefore decaying, nature of its products, which go under the designation of caseous or yellow tubercle. In a person of this constitution also, the grey consolidation, diffused and granular,1 may arise in the lungs without further cause than casual congestions or catarrhs, and sometimes without even these.

It would take up too much of our space to trace this subject through all the handlings which it has received from various observers and commentators during the forty years which have elapsed since the above stated views were published; but so much light has been obtained from certain lines of research, that it will be necessary to give a brief account of the best ascertained facts concerning them, which may be ranged under these three heads:— On the Nature and changes of tubercle and kindred matters, which will lead to the subject of Caseation, or Fatty degeneration of tissues, and, in conclusion, to the Artificial production of tubercle by inoculation, &c.

''The constant form and shape that these miliary granulations present become another matter of enquiry, and it seems probable that they are some elementary part of the lungs in a state of chronic inflammation. Broussais conceives them to be the lymphatic glands, whilst Andral considers them as the individual vesicles, or single terminations of the bronchi.'Rational Exposition, See. 1828, p. 157. The question which I thus proposed so long ago has only recently been answered by the sagacious and careful investigations of Drs. Burdon Sanderson and Wilson Fox, who have pretty well proved that these granulations are hypertrophied portions of the adenoid or lymphatic glandular tissue, which is a normal constituent of the lung and other organs—in a measure thus verifying the conjecture of Broussais, and that independently expressed by Dr. Abercrombie in the passage before quoted.

CHAPTER III.

ON THE NATURE OF TUBEBCLE AND OTHER PHTHINOPLASMS.

MicrologyGulliver, Addison, Rokitansky, Lebert, GrubyHistology of Tubercle—Cellular PathologyVirchow's Views objected toTubercle and Cancer contrastedBurdon Sanderson's conclusionsPortals anticipation of the lymphatic nature of Tubercle.

The microscopical observations of Mr. Gulliver on tubercle,1 published in 1842, '3, and '4, are more original and accurate than those of many others who have succeeded him, and have been confirmed by the most careful recent observers. He described young or grey tubercles as chiefly composed of cells; but crude or yellow tubercle of shrinking, blighted, shapeless, degenerating cells, with preponderance of granular matter and oily particles. The site of pulmonary tubercles (grey and yellow ?) Mr. Gulliver described to be both inside and outside of the air cells; and their endowments to be very low in the scale of organisation, so that, devoid of inherent power of growth possessed by the cells from which they originated or increased, they only retrograde or degenerate into amorphous lifeless corpuscles, and into gramdar and molecular fatty matter, all incapable of organisation.

About the same date appeared the independent observations of Dr. W. Addison, which, so far as related to the structure of tubercle, were very similar to those of Mr. GuUiver.8

1 Appendix to Gerber's Anatomy, 1842, Plates 29 and 31 ; Notes to Boyd's Vital Statisties; Edin. Med. and Surg. Journal, July 1843; and Willis's Translation of Wagner's Physiology, 1844, p. 360.

S 'The semitransparent forms of tubercle and tubercular infiltration owe their peculiarity to a great relative amount of granulated vesicles ; whereas MICROLOGY OF TUBERCLE, ETC.

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Some years later Eokitansky described tubercles as consisting of a more or less pellucid base with elementary granules of various magnitudes, nucleus formations in various phases, and scanty nucleated cells. He considered tubercle, as I had done long before, as an altered fibrinous exudation from the vessels; miliary tubercle corresponding with the fibrinous (fibrillated), and yellow tubercle with the croupous (corpuscular) variety of lymph. More recently Mandl1 pushed this view to an extreme, in describing tubercle as an amorphous matter consisting of mere granules or molecules, and as unorganised albumen subject to fatty transformation.

On the other hand, Lebert, Gluge, Gruby, E. Hall, and others described a peculiar form of cell or corpuscle as characterising tubercle; just as particular forms of cell distinguish cancer. Had these last descriptions been accurate, they would have gone far to establish Laennec's notion of the specific character of tubercle as a heterologous growth, instead of being, as I supposed, a cacoplastic exudation or product. But these peculiar tubercle corpuscles have not been recognised by subsequent observers ; the cell formation present in miliary tubercles not differing from those in inflammatory exudations, or even those normally existing in the lymphatic glands and vessels. (Burdon Sanderson.)

But a very important influence on the views concerning tubercles, and all other tissue changes, was brought to bear in the hypothesis of the cellular physiology and pathology, originating in the researches of Schleiden and Schwann, and erected into a system by Virchow and others, represented in the axiom, ' omnis cellula e cellula.'

Without attempting to enter on a discussion of cellular pathology in general, we quote Virchow's description of

the opaque white forms of tubercle are attributable to great numbers of isolated granules.'—Trans. Prov. Med. and Surg. Assoc., 1843, p. 287. 1 Archives gen. de Mid., 1855.

grey granular tubercle, this being the typical form of the product:—

I am of opinion that a tubercle is a granule or a knot, and that this knot constitutes a new formation, and indeed one which from the time of its earliest formation is necessarily of a cellular nature, and generally, just like all other new formations, has its origin in the connective tissue, and which, when it has reached a certain degree of development, constitutes a minute knot within this tissue, that, when it is at the surface, projects in the form of a little protuberance, and consists throughout its whole mass of small uni- or multi-nuclear cells. What especially characterises this formation is the circumstance that it is extremely rich in nuclei, so that when it is examined as it lies embedded in the tissue which invests it, at the first glance there seems to be scarcely anything else than nuclei; but upon isolating the constituents of this mass, either very small cells provided with one nucleus are obtained—and these often so small that the membrane closely invests the nucleus—or larger cells, with a manifest division of the nuclei, so that from twelve to twenty-four or thirty are contained in one cell, in which case, however, the nuclei are always small, and have a homogeneous and somewhat shining appearance. This structure, which in its development is comparatively most- nearly related to pus, inasmuch as it has the smallest nuclei, and relatively the smallest cells, is distinguished from all the more highly organised forms of cancer, cancroid, and sarcoma, by the circumstance that these contain large, voluminous, nay, often gigantic corpuscles, with highly developed nuclei and nucleoli. Tubercle, on the contrary, is always a pitiful production, a new formation, from its very outset miserable. From its very commencement it is, like other new formations, not unfrequently pervaded by vessels; but when it enlarges, its many little cells throng so closely together that the vessels gradually become completely impervious, and only the larger ones, which traverse the tubercle, remain intact Generally fatty degeneration sets in very early in the centre of the knot (granule), where the oldest cells lie, but usually does not become complete. Then every trace of fluid disappears, the corpuscles begin to shrivel, the centre becomes yellow and opaque, and a yellowish spot is seen in the middle of the grey translucent granule. This is the commencement of the cheesy metamorphosis which subsequently characterises the tubercle. The change advances from cell to cell, farther and farther outwards, and it not unfrequently happens that the whole granule is gradually involved in it.1

1 Virchow's Cellular Pathology, translated by Dr. Chance, 1860, p. 475-7. ARE TUBERCLES GROWTHS?

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Now, whilst I admit that these observations prove grey tubercles to have a more definite organisation than I was wont to ascribe to them in my earlier writings, I would call the reader's attention particularly to the passages from this author which I have put in italies. They amount to an admission that granular tubercle in its form and history has more resemblance to pus than to the more organised structures which are properly denominated growths, such as cancer, sarcoma, &c.; and I therefore, and for many other reasons, still maintain that grey tubercles have more affinity to the class of cacoplastic hypertrophies or cacoplastic deposits than to that of new growths. It is true that Virchow assigns them to a distinct class, under the term of lymphoma, because they possess the same kind of structure as that found in natural lymphatic glands; and I am quite willing to acknowledge a close affinity between lymphatic glandular swellings and tubercles; for they affect the same subjects, and run a similar course. But these glandular swellings also have a close resemblance on the one hand to swellings from inflammation, and on the other to the simple enlargement of the spleen and liver occurring in leucaemia. In both these cases there is doubtless hypertrophy or hyperplasia, but this may be in the way of exudation or cell proliferation, without the development of complex tissue which constitutes a growth. If the addition of cells, fibres, and other products of inflammation in a tissue, constitutes a growth, then common cutaneous pimples, tubercles, and boils, are growths, and the swelling from erysipelas or cellulitis must be included under the same term; but surely this would exceed its usual acceptation.

Even if it be admitted that tubercles are in any sense entitled to the appellation of growths, it is of great importance to distinguish them from cancers and other formations, to which the term growth is more commonly and

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