CONGRESS ON TUBERCULOSIS. 
447 
some cases the tubercle-bacilli or the sputum were injected un¬ 
der the skin, in others into the peritoneal cavity, in others into 
the jugular vein. Six animals were fed with tubercular sputum 
almost daily for seven or eight months ; four repeatedly inhaled 
great quantities of bacilli, which were distributed in water, and 
scattered with it in the form of spray. None of these cattle 
(there were nineteen of them) showed any symptoms of disease, 
and they gained considerably in weight. From six to eight 
months after the beginning of the experiments they were killed. 
In their internal organs not a trace of tuberculosis was found. 
Only at the places where the injections had been made small 
suppurative foci had formed, in which few tubercle-bacilli could 
be found. This is exactly what one finds when one injects dead 
tubercle-bacilli under the skin of animals liable to contagion. 
So the animals we experimented on were affected by the living 
bacilli of human tuberculosis exactly as they would have been 
by dead ones; they were absolutely insusceptible to them. 
The result was utterly different, however, when the same 
experiment was made on cattle free from tuberculosis with 
tubercle-bacilli that came from the lungs of an animal suffering 
from bovine tuberculosis. After an incubation-period of about 
a week the severest tubercular disorders of the internal organs 
broke out in all the infected animals. It was all one whether 
the infecting matter had been injected only under the skin or 
into the peritoneal cavity or the vascular system. High fever 
set in, and the animals became weak and lean ; some of them 
died after a month and a half to two months, others were killed 
in a miserably sick condition after three months. After death 
extensive tubercular infiltrations were found at the place where 
the injections had been made, and in the neighboring lymphatic 
glands, and also far advanced alterations of the internal organs, 
especially the lungs and the spleen. In the cases in which the 
injection had been made into the peritoneal cavity the tuber¬ 
cular growths which are so characteristic of bovine tuberculosis 
were found on the omentum and peritoneum. In short, the 
cattle proved just as susceptible to Infection by the bacillus of 
bovine tuberculosis as they had proved insusceptible to Infection 
by the bacillus of human tuberculosis. I wish only to add that 
preparations of the organs of the cattle which were artificially 
infected with bovine tuberculosis in these experiments are ex¬ 
hibited in the Museum of Pathology and Bacteriology. 
An almost equally striking distinction between human and 
bovine tuberculosis was brought to light by a feeding experi- 
