and give rise to acute affections. There is very much reason to believe that they originate most of the serious visceral diseases which are so common. Very many cases of granular degeneration of the kidney, of cirrhosis of the liver, of contracted orifices of the heart, proceed, in our opinion, from slow and gradual textural changes, dependent on an unhealthy crasis of the blood. The importance of being aware of this, in the treatment of these affections, is abundantly manifest. As, however, our knowledge of these conditions of the blood is yet very imperfect, we shall not attempt more than to indicate shortly the principal features of the several crases, as they are enumerated by Rokitansky: A crasis may occur as the primitive affection, and its local manifestation, when it takes place, be determined, as to its seat, either by external influences, or by the operation of the nervous system. Or it may be consecutive, arising as the consequence of a local, morbid process, which has caused infection of the general mass of the blood by matter absorbed, or having undergone a deteriorating change within the vessels. A crasis may terminate, either by return to the healthy condition, or by conversion into another morbid crasis, or by destruction of life.

The fibrinous crasis corresponds to the condition of blood, which may be termed phlogistic or inflammatory. It is characterized by an increased tendency of the fibrin to coagulation, and to separation in a solid form, either in some part of the vascular system, or as an exudation in some of the tissues. For the development of this crasis, Rokitansky considers it necessary that the respiratory function should be freely performed. In most cases, the quantity of fibrin in the blood is much increased; but this is not so essential a feature as the alteration of its quality. In the croupous variety of this crasis both the coagula and the exudations show less tendency to organization; on the contrary, they tend to break up themselves, and often corrode, and, as it were, fuse down the tissues in which they are deposited. The mucous surface

of the respiratory and digestive canals, serous and synovial membranes, are the chief seats of such exudations. The croup of early life, many pneumonias, many cases of puerperal peritonitis or phlebitis, acute rheumatism, and endocarditis, are so many examples of disease intimately connected with this crasis. Fibrinous crases often appear epidemically. It may be fairly asked, whether the condition of the blood may not be always produced by the inflammation. We are, however, quite of Rokitansky's opinion, that while, in many instances, there is no doubt that such is the case, yet that there are numerous others in which the local inflammation is the result of a foregoing crasis. The marked disproportion that is sometimes observed between the hyperæmia and the exudation, and the early occurrence of the latter in many cases, appear to us to argue strongly in favor of this view.

Rokitansky recognizes an aphthous variety of the fibrinous crasis, which gives rise to the exudations of muguet, diphtheritis, some dysenteries, and of hospital gangrene. These are manifestly outpourings of deteriorated diseased fibrin on various surfaces, rather than products of local inflammation. The alteration of the blood in these instances. must certainly be primary.

THE TUBERCULOUS CRASIS-TUBERCLE.

The product of this crasis, from which it has its name, is the wellknown substance, which, on account of its frequently spherical shape, is called tubercle. This we have not yet described; and though Rokitansky places it among the organized new formations, yet we think it will be more convenient to make mention of it here, in connection with our remarks upon the condition of the blood in which it originates. Tubercle, or tuberculous matter is, in almost all cases, an exudation of protein material, which speedily passes into the solid form, and never proceeds beyond the lowest grade of development. It very commonly assumes a spherical shape, which appears to depend partly upon its enlarging from its original magnitude by successive accretions to its surface, and partly on the nature of the tissue in which it is deposited. There are two principal varieties of tuberculous matter, distinguished as gray

Fig. 28.

and yellow tubercle. The former, sometimes called gray granulations, are about the size of a millet-seed, roundish, resisting under pressure, of a grayish, semi-transparent aspect. The microscope shows them to consist of a basis-substance (blastematous), which is solid and homogeneous, and serves as the uniting medium of certain corpuscular elements. These are granules commonly of oily aspect, nuclei, oval, or more elongated, generally feebly formed, and cells, which are, for the most part, very few in number, and probably not to be regarded as any essential part of the tubercle itself. The globules of tubercle, which M. Lebert describes as characteristic of this morbid product, are nothing more than the ill

Gray tubercle; miliary granulation.

developed nuclei just mentioned. Rokitansky applies to them the following epithets: "anomalously shaped, irregular, as if gnawed, angular, bent, constricted, rudimentary, stunted." The elements of the tissue in which it is deposited, are often found imbedded in the mass. This, however, scarcely applies, except to those which are not very readily

destroyed, as fibres. No vessels are ever found in separate tubercles; some traces of those belonging to the tissue may be imprisoned in the interspaces of several aggregated together. Yellow tubercle forms masses of varying size, but generally somewhat larger than those of the gray, equalling, perhaps, a hemp seed, or a pea, in magnitude. They are from the outset opaque, of a whitish-yellow color, of rather brittle consistence. Their microscopic structure is nearly identical with that of the preceding variety, only that they contain more diffused granular matter. Their relations, also, to the surrounding textures, are quite similar to those above mentioned. The yellow tubercle, which Rokitansky denominates the croupo-fibrinous, in opposition to the gray, which is the simple fibrinous, undergoes two metamorphoses of very great importance; one is that of softening, the other that of cretification. Softening consists in the texture of the mass becoming more lax and moist, with notable increase of size, the change proceeding till it breaks up into a yellowish, diffluent, cheesy mass, which finally becomes a thin, whey-like fluid, of acid reaction, containing minute flocculi. The change seems first to affect the homogeneous basis-substance, which dissolves into a kind of fluid, loaded with pulverulent molecules; the corpuscular elements in consequence of this are set free, and, at the same time, are themselves more or less corroded and dissolved. The softened tubercle thus consists of (1) a fluid loaded with diffused granulous matter; (2) traces of altered nuclei and cells; (3) free oil in the form of various-sized drops. It may also contain debris of the tissues. cretifying change consists in the gradual deposition and liberation of calcareous particles in the tuberculous mass, together with simultaneous absorption of the animal matter, and consequent decrease in size. It is said by Rokitansky never to take place except in softening, or softened tubercle; but this is, probably, too absolute an assertion. The cretified tubercle very often remains as a hard, irregular mass, surrounded by indurated tissue, and appears to be insusceptible of further change; sometimes,

The

Fig. 30.

Isolated tubercle corpuscles. On the right are four blood-globules.

Fig. 31. Tubercle corpuscles from the peritoneum. a. The same, after the addition of acetic acid.

Fig. 32. Tubercle corpuscles, granules, and molecules, from a soft tubercular mass in the lung. 250

diameters linear.

however, absorption proceeds further, and almost the whole of the deposit is removed. When this is the case, however, it is probable that

Fig. 35. Pus-corpuscles. One shows the double granular nucleus after the addition of acetic acid.
Fig. 36. Plastic or pyoid corpuscles.

Fig. 37. Granular corpuscles from cerebral softening.

Fig. 38. Cancer-cells from the uterus. 250 diameters linear.

Fig. 39. Structure of the central portion of a tubercular mass, imbedded in the cerebellum.

Fig. 40. Structure of the external portion of the same mass, where it was in contact with softened cere bellar substance. 250 diameters linear.

Fig. 41.

absorption had predominated over the deposition of calcareous matter from the first. The only metamorphosis, according to Rokitansky, which the gray tubercle undergoes, is a kind of drying up into a hornlike substance, which, in some cases, is also the seat of calcareous deposit. This he calls obsolescence. It has been very commonly held, since the time of Laennec, that the gray tubercle, or gray granulation, was the nascent phase of the yellow: Dr. Walshe, after careful examination, maintains this view; Hasse and Rokitansky reject it. The latter regards the two as essentially distinct, though very frequently combined together in the same tubercle, in varying proportions; and remarks, with much reason, that it is an error to look upon these differences in composition as stages of transition, or conversion of one into the other. The apparent softening of the gray tubercle, when it occurs, is not dependent upon an alteration in its own substance, but in that of the yellow mingled with it. It is very interesting to remark how the behavior of the two kinds of tubercle corresponds with that of the fibrin, from which they seem to be derived. The gray resembles healthy fibrin in its tendency to contract and shrink up into an indurated mass; the yellow, like the croupous fibrin of coagula and exudations, tends to soften and break up into a fluid substance. Moreover, as the masses of croupous fibrin begin

Fragments of phosphate of lime, crystals of cholesterin,

and tubercle corpuscles, from a cretaceous mass in the lungs.

to soften in their central part, so we find does the yellow tubercle. Dr. Carswell and others consider that inflammation and suppuration taking place in the tissues surrounding the tubercles, are the chief cause of its softening and breaking down. This Rokitansky denies; but though we believe with him that the softening change is one inherent in the tubercle-substance itself, yet we think the hyperæmic movement taking place around it must, at least, give an impulse to the process. As each tubercle, or group of tubercles, undergoes softening, the space which it occupied becomes the cavity of a minute abscess, the contents of which, sooner or later, are evacuated. The tissue involved in the tubercle is, of course, destroyed, together with it, but rather in the way of necrosis than of ulceration. The tendency of the tubercle to soften differs very greatly in different cases. Sometimes it is scarcely deposited before it begins to break down, sometimes it remains very long in its original (crude) state. The influence of the inflammation set up around tubercles upon their progress varies very much, chiefly according to the degree of the tuberculous dyscrasia. If this be very great, the result of the induced hyperemia will be the infiltration of the bordering tissues with tuberculous matter of the lowest kind, tending to rapid diffluence, and involving in its destruction that of the infiltrated tissue. The increase of a tuberculous cavity in this way may be most rapid. On the other hand (and herein is contained a truth of the utmost interest to the practitioner), if the dyscrasic condition of the blood be slight originally, or if it have been amended by well-directed treatment, inflammation gives rise to the exudation of fibrin, which develops itself into the so-called induration tissue, or fibroid callus, which either surrounds and capsulates the tubercle, or forms a wall to and contracts the cavity, if one has formed. The surrounding tissues are often much puckered by the shrinking in of the fibrinous deposit. There occur occasionally, especially upon serous surfaces, small granulations which have much the aspect of tubercles, but which, in their progress, assume more of a fibroid texture; these may be regarded as specimens of an intermediate condition between tubercle and fibrinous exudation, and are, in this light, of great interest. Tubercle seems sometimes to be deposited in the way of infiltration; that is to say, it no longer forms the small characteristic tubera, from which its name is derived, but appears as a uniform mass which had been effused into the tissue in a fluid state, and had solidified there. The common tuberculization of the absorbent glands is very much of this kind; it is seen, however, most strikingly, in the lungs, a whole lobe or more of which may appear to be converted into a tuberculous mass. Sometimes this appearance depends on the part being occupied by numerous tubercles, crowded together; but then there can always be distinguished on a section interposed layers of pulmonary tissue which are not seen in real infiltration. The only doubt as to the real nature of apparent tuberculous infiltration arises from the great similarity between chronic pneumonic consolidation and this state, so that Dr. Walshe is inclined to consider them identical. Our own belief is, that in a person whose blood is in a high degree affected by the tuberculous dyscrasia, inflammatory hyperæmia may result in the exudation of a material which corresponds closely with tuberculous, but