426 
NOCARD AND ROSSIGNOL. 
ulcerated. Nowhere on the intestinal mucous membrane are to 
be found any tubercles or ulcerations. 
CONCLUSIONS. 
From these experiments we infer, ist. That ingestion con¬ 
stitutes a mode of contamination much less efficacious than in¬ 
halation. 
One cow resisted infection although she ingested large 
quantities of tuberculous material. 
Three others were infected, but in one of them it was im¬ 
possible to locate the lesion, which had been determined by the 
use of tuberculin, while in the remaining two the tubercular 
lesions were so small that in a less critical autopsy they would 
•certainly have been overlooked. 
The calf itself, which since its birth was fed on milk from 
cows io and n, a milk extremely rich in Koch’s bacilli, was 
infected only to a slight degree. 
The period of incubation has varied from 32 to 48 days. 
2d. The respiratory organs constitute the most common and 
most efficacious means of tubercular infection. 
The results are about the same when the tuberculous mate¬ 
rial is inhaled in a state of dry impalpable dust, or in a state of 
fine liquid particles containing bacilli, as is the case when a 
tuberculous animal coughs or snorts in the vicinity of sound 
animals. 
The period of incubation has varied from 19 to 32 days. 
The direct injection into the trachea did not give the results 
that some had expected. 
The lungs completely escaped the infection. It was be¬ 
cause the liquid injections did not reach the pulmonary cells; 
they did not get beyond the small bronchi, on account of the 
phagocy’.al resistance of the bronchial mucosa. 
The bacilli injected were absorbed by the phagocytes and 
thrown out in the mucus of expectoration. In the animals in¬ 
fected through the inhalation of dry or liquid dusts, the bronchi, 
the small bronchi and the pulmonary alveoli have escaped the 
infection ; the tuberculous nodules had their seat under the 
