THE LUNG PLAGUE. 05 



which the pathological lesions were essentially similar to those which I had observed in 

 cattle. 



The appearances presented to the naked eye in all the cases which I had occasion to 

 study agreed quite well with the excellent account given by Professor F. Weber, of Kiel, 

 in 1854.* I did not, however, have any opportunity of observing the separation and 

 encapsuling of isolated lung lobules described by that writer as occurring in chronic cases. 

 The general aspect of the lesions may be described as follows : 



The pleural cavity of the affected side contained a variable quantity of clear, 

 opalescent, turbid, or even grumous, yellowish serum, and the parietal as well as the 

 pulmonary pleura was plastered over, to a variable extent, with masses of opaque whitish 

 yellow, or greenish yellow, fatty-looking lymph, flakes of which frequently floated in the 

 serum. Not unfrequently both sides were similarly affected. In some cases the pericar 

 dium contained serum of the same character, with adherent lymph coating its inner 

 surface and covering the heart. The adipose tissue about the pericardium often exhibited 

 a peculiar transformation, which caused its appearance to the naked eye to approximate 

 closely to that of the adjacent lymph masses 



A section of the lung most generally showed its apex nearly healthy ; further down 

 the parenchyma was congested and cedematous; still lower the connective tissue septa 

 between the lung lobules were progressively thickened, until finally they were converted 

 into whitish, yellowish, or greenish opaque layers, which in sections of the organ appeared 

 to map out the congested and cedematous lung tissue into angular territories, readily 

 recognized as lung lobules. Still further toward the diaphragm the lung parenchyma 

 between the opaque yellowish septa exhibited various degrees of red hepatization, while 

 in the most inferior portions of the organ the lung tissue, having passed into the stage of 

 gray hepatization, could not readily be distinguished by the naked eye from the tissue of 

 the diseased interlobular septa, and the surface of these portions of the section appeared 

 of a mottled reddish yellow or yellowish gray hue. 



An examination of the pleural surface, after sections of the lung were made, 

 showed, as a rule, that the adherent lymph masses on the pleura pulmonalis corresponded 

 chiefly to those portions of the lung which were more or less completely hepatized. 



Very great variation in the extent of the disease was noted in different cases. Some 

 times one lung only was affected, sometimes both. Some animals died before any portion 

 of the lung had passed into the stage of gray hepatization; others survived till abscess 

 formation, or even gangrene of portions of the lung tissue supervened. Sometimes at 

 least one of the lungs was hepatized, more or less completely, throughout its whole extent, 

 but generally the upper lobes were nearly healthy, or at most had not progressed beyond 

 the stage of congestion or oedema. When sections of the diseased lung were laid on a 

 suitable perforated plate considerable quantities of bloody serum drained from them. 



The peculiar appearance produced by the yellowish thickening of the interlobular 

 septa, combined with cedema and congestion, or red hepatization of the parenchyma of 

 the lobules involved, was seldom absent from some portion of the affected lung. This is 

 the phenomenon most likely to arrest the attention of observers familiar with the post 

 mortem appearances of pleuropneumonia in the human subject, when their attention is 



* Die interlobuliire Pneumonic. Virchow s Arcbiv., Bd. vi, S. 89. 



