ETIOLOGY OF TUBERCULOSIS. 
101 
pigs. Three of them died in the fifth and sixth weeks, the others were killed 
some days later. All tuberculous. 
23. Perlsucht knot from the lung , partly with caseous contents, and not 
very rich in bacilli. Seven guinea pigs. Five of them died up to the seventh 
week. The last two were killed in the eighth week. All tuberculous. 
24. Calcareous perlsucht knot from the peritoneum with many bacilli. 
Three guinea pigs ; these died up to the sixth week. All tuberculous. 
25. Caseous pneumonia of pig. —Thickened, very bacilli-ricli lung tissue. 
Five guinea pigs. These died in the fifth and sixth week and were tuberculous. 
26. From the lung tubercles of a rabbit which died of spontaneous tubercu¬ 
losis, four guinea pigs were inoculated. Two of these died in the seventh week, 
two were killed in the eighth week. They were all tuberculous. Four guinea 
pigs were again inoculated from the first of these animals, two guinea pigs and 
four rabbits from the second, two rabbits from the third, a;id one guinea pig and 
one rabbit from the fourth. The guinea pigs were inoculated subcutaneously, the 
rabbits in the anterior eye-chamber. The guinea pigs died up to the seventh week 
of tuberculosis, the rabbits all were attacked with iris-tuberculosis; two died in 
the ninth and tenth week of tuberculosis, the others were then killed and more or 
less lung tubercles were found in them. 
27. Two guinea pigs and two cats were inoculated with lung tubercles from 
a monkey , which died of spontaneous tuberculosis. The two guinea pigs died in 
the sixth week, one cat in the seventh, the other after thirteen weeks. All tuber¬ 
culous. Six guinea pigs and one rabbit (in the anterior eye-chamber), were then 
inoculated from one of the guinea pigs and these were all found to be tuberculous 
before the eighth week (partly died, partly killed). Finally from two animals of 
this second group the tuberculosis was reinoculated into seven other guinea pigs 
with success. Also from one of the cats four guinea pigs were successfully inoc¬ 
ulated. It is still to be mentioned that four guinea pigs were inoculated with the 
spleen of this monkey, which had been dried fifty-six days and with the lung 
tubercles of the same, which had lain fifty-seven days in absolute alcohol. These 
animals for four months showed no change, were then killed and proved them¬ 
selves free of tuberculosis. 
28. From a second monkey which died of spontaneous tuberculosis two 
guinea pigs were inoculated with lung tubercles and died of tuberculosis in the 
eighth and ninth weeks. Further : from these guinea pigs two guinea pigs and 
one rabbit were inoculated. As these appeared already diseased in the sixth 
week, they were killed and found tuberculous. Two guinea pigs were inoculated 
with lung tubercles of the same monkey which had been dried and preserved 
three days. These animals were also killed in the sixth week and found tuber¬ 
culous. 
These experiments in inoculation which have just been enumerated were 
made upon one hundred and seventy-nine guinea pigs, thirty-five rabbits and four 
cats, and the inoculation had as a consequence tuberculosis in every case without 
exception. Moreover the presence of tuberculous changes did not confine itself 
to single knots of a doubtful nature in one or the other organ, but in every single 
case the tuberculosis could be proved with all the certainty wished, first, by the 
development of the characteristic symptoms of the disease, such as swelling of the 
