.ETIOLOGY OF TUBERCULOSIS. 
121 
bacilli-bearing liquids. Usually the inoculation took place in one side of the 
belly, and the lymph-glands situated next to the point of inoculation were 
found considerably swollen and caseous. The bronchial glands, on the con¬ 
trary, were almost always so small that they could scarcely be found. Also 
in these cases the liver and spleen had undergone the greatest tuberculous 
changes, while the tubercles in the lungs were still comparatively small. In 
the case of animals infected by inhalation, which had always taken consider¬ 
able numbers of bacilli into the lungs, there were found corresponding to this, 
not one or a few great herds, but a very large number of little tubercles in the 
lungs. If one considers these experiences gained from artificially infected 
animals, then he will be obliged to represent to himself the spontaneous tuber¬ 
culosis, as it occurred under the above mentioned circumstances in guinea pigs 
and rabbits, as having arisen through inhalation of one or more infectious germs, 
that is bacilli. 
Of this sort of spontaneously-diseased animals I have examined seventeen 
guinea pigs and eight rabbits, among them a wild rabbit, which, as the only 
one of ten animals of the same sort, died after three months’ imprisonment, 
tuberculous in a high degree. These all had many, in some cases indeed ex¬ 
traordinarily numerous bacilli in the surroundings of the caseous herds of the 
lungs. In the secondarily arisen tubercles the number of bacilli was usually 
less. It seems to me worthy of mention, that many times, in the larger caseous 
herds of the lungs, the central dissolution was very far advanced, and in con¬ 
sequence of the same complete cavities, though of slight extent, had formed. 
Up to a certain degree spontaneous-inhalation-tuberculosis brings on conditions 
in these animals which are analogous to those of human phthisis. The infec¬ 
tion only does not remain long enough localized, it spreads too early to other 
regions of the body and leads thereby to the death of the animal before import¬ 
ant cavities can form as they occur in the human lung. 
Tuberculosis of the remaining organs takes a very peculiar course in both 
the rabbit and the guinea pig, and moreover a different one in each. In the 
beginning, in both sorts of animals, the tuberculous knots in the liver and 
spleen have the usual characteristic appearance which they maintain in the 
lungs. They are miliary, gray looking little knots, with yellowish centre, and 
of a quite compact consistence. In guinea pigs the spleen is decidedly enlarged, 
and of a blackish-red color, on which background the grayish knots show 
very plainly. Very soon, however, the tubercles become confluent and there 
arise larger whitish gray islands. These too increase constantly and give the 
spleen a light grayish-red and blackish-red marbled appearance. Finally the 
light parts get the upper hand, and the spleen can then take a wholly unusual 
appearance, which does not in the least suggest the origin of this condition in 
tuberculosis, especially when it comes to little ruptures and hemorrhages in 
the fragile spleen-substance, by which it gets a still gayer coloring. At all 
events it is very peculiar that tuberculosis in the spleen of the guinea pig leads 
to such widespread “ congulation-necrosis,” but never to genuine caseous de¬ 
generation, while in the lymph-glands of these animals a decided caseous de¬ 
generation occurs. The liver of the guinea pig acts in an exactly similar 
manner. In the first place gray disseminated knots form, lighter parts appear, 
