Contrary to the received opinion, we assert that the liver is rarely the seat of tubercular disease. It scarcely ever occurs in this organ as a primary affection, but is not unfrequently found as a secondary complication of advanced primary tuberculosis in another organ, or of universal tubercular disease. It must, therefore, almost always be considered as the expression of advanced tubercular cachexia.

Hepatic tubercle occurs in the shape of semi-transparent, grayish, crude, miliary granulations; in which case it is more especially the product of acute tuberculosis; or as yellow, cheesy, adipose deposits, of the size of a hemp-seed, or pea, or more. It is consequently often larger than pulmonary tubercle; but, on the other hand, with the exception of very rare cases, is much less extensively disseminated than the latter.

Hepatic tubercle is not limited in its seat to a particular section of the viscus, but attacks all portions indiscriminately, and the more so, the acuter its course.

The tubercular matter is deposited in the parenchymatous cellular tissue of the organ, and especially in that pertaining to the biliary capillaries. It very frequently surrounds a minute gall-duct, and thus presents a central canal, which gives rise to a biliary discoloration of the nucleus.

When the liver is attacked by acute tuberculosis, its appearance resembles the parenchyma of other organs similarly affected; it is in a peculiar state of turgescence, the tissue is relaxed, friable and pale, and gorged with a serous or sero-sanguineous fluid. All this will be the more evident, the more rapidly the tubercular deposit is effected, and the more the universal cachexia is developed.

The conditions under which hepatic tubercle occurs, render it apparent that it rarely passes into the stage of softening, and scarcely ever into that of cretification; the constitutional affection generally proves fatal from its violence and diffusion, before the tubercles of the liver have undergone these metamorphoses. Still we do occasionally find that, from the very violence of the constitutional affection, a solution of hepatic tubercle is effected; and then it is probably the yellow variety which is converted into a primary hepatic vomica, and which offers no peculiar characters beyond the biliary discoloration of its contents.

We do not, however, meet with a condition accompanying tubercular suppuration in the liver which may be considered analogous to pulmonary phthisis.

This vomica requires to be the more carefully distinguished from morbid dilatation of the gall-ducts, as the latter not only occurs frequently or almost invariably, in combination with hepatic tubercle, but is not unfrequently coexistent with tubercular disease of other organs. In this case small cavities, of the size of a millet-seed or a pea, filled with viscid, muco-bilious, dirty green matter, with flaccid parietes, are found scattered through the liver, which on close examination are found not to be tubercular, but to be dilatations of capillary gall-ducts. The hepatic tubercles exist at the same time, and at various distances; a tubercle may occasionally be found near one of these cavities, but it is not characterized by the symptoms of secondary deposit accompanying the fusion of tubercular matter.

The conditions of their origin, and their connection with the constitutional disease, have not been as yet ascertained; but we are warranted by numerous observations in stating, that they invariably indicate a high degree of the constitutional affection; and a tendency to universal tubercular deposition, and especially in the abdominal viscera.

Hepatic tubercle may be complicated with tubercular affections of almost all organs, as might be assumed from its originating in an advanced stage of tubercular dyscrasia; however, the abdominal organs are found chiefly implicated, viz. the abdominal lymphatic glands, the spleen, the peritoneum, and the intestinal canal.