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R. KOCH. 
the impression of multiple abscesses than of tubercles. Beside these, to be 
sure, the typical forms of the grey tubercle with the yellowish centre occur 
in the lungs, on the pleura and the omentum. But these are also of various 
sizes and one gains the impression that the spread of the tuberculous virus in 
the monkey does not take place all at once, as in miliary tuberculosis in man, 
but is continuous and only in small quantities. 
The number of tuberculous monkeys examined by me amounts to eight. 
In all these the disease had risen spontaneously, and apparantly the first infec¬ 
tious herd still existed in the lung. Only in one case had the tuberculosis 
proceeded from the cavitas navium. An abscess had formed in the nasal duct, 
which was probably caused by a wound from a scratch at the entrance of the 
nose, and had spread constantly but slowly farther upon the septum and the 
turbinated bones. The submaxilary lymph-glands swelled and became puru¬ 
lent. Not until then did the previously active and strong animal have trouble 
in breathing and become emaciated. In the dissection very numerous tubercles 
of varying size were found in the lung, spleen, liver and omentum. 
In all the cases the tuberculous bacilli could be proved, and, moreover, 
in tile tubercles of the most different organs. Nevertheless the number of 
bacilli was not very large. 
7.—Spontaneous Tubekculosis of Guinea Pigs and Rabbits. 
Among many hundred rabbits and guinea pigs, which were bought for 
experimental purposes, were experimentally used and were finally dissected, 
there was not a single animal which was tuberculous. Not until after the 
attempts at infection with tuberculous substances had begun and a large num¬ 
ber of tuberculous animals found themselves in separate cages, but in the same 
room with other animals, single cases of spontaneous tuberculosis occurred 
among the latter. Nevertheless plainly visible symptoms of tuberculosis hardly 
ever showed themselves in such animals until they had spent three to four months 
in a room with tuberculous animals. It was a very characteristic appearance 
also,that when the number of artificially infected tuberculous animals decreased, 
the cases of spontaneous tuberculosis became correspondingly rare; the 
reverse being also true. For a considerable time, when only very few tuber¬ 
culous animals were kept in the space used for such experiments, the spon¬ 
taneous tuberculosis among the other very numerous guinea pigs and rabbits 
ceased entirely. The changes which were found in the animals dying from 
spontaneous tuberculosis distinguish themselves from those caused by artificial 
infection in a very characteristic manner, so that the varying methods of in¬ 
fection can be recognized with all certainty. There were regularly in animals 
dying with spontaneous tuberculosis one or more large tuberculous herds in 
the lungs, which were far advanced in caseous degeneration and at the same 
time decidedly enlarged and caseous bronchial glands. A few times larger 
herds were wanting in the lungs, only the bronchial glands were extraordinarily 
large and filled with caseous contents. The tuberculous changes had made 
in the other organs comparatively little progress. 
The artificially infected animals conducted themselves differently according 
as they were infected by subcutaneous inoculation or by the inhalation of 
