290 PUBLIC HEALTH BACTERIOLOGY 



cutaneous inoculation ; intraperitoneally, the bacilli mul- 

 tiply in the body but do not produce tubercles. 



Dogs are highly resistant to subcutaneous inoculation, 

 but succumb to general tuberculosis when large doses are 

 given intravenously or intraperitoneally. 



In the fowl, intravenous injection of bovine tubercle 

 bacilli caused death in 50 per cent, with wasting, cedema 

 of lung, and pallor of liver. In a few, definite tubercles 

 were found in the lungs and minute necrotic areas in the 

 liver. Death is apparently due to toxaemia, as dead bacilli 

 have the same effects. Intraperitoneally and intramuscu- 

 larly, even in large doses, only local lesions are produced, 

 and there is no dissemination. 



Horses : subcutaneously or orally, no progressive 

 tuberculosis is produced. Intravenously, 10 mgr. cause 

 death from acute tuberculosis in twenty days. 



(d). Stability in culture. Subcultured for long periods, 

 (one case, 1487 days = 4 years), no great loss of virulence 

 was found. 



2. Human tubercle bacillus. The human type is taken 

 as that bacillus which has been found in the majority of 

 cases of human tuberculosis. Its chief characters are : 

 on serum, it grows more rapidly than the bovine type, 

 hence it is called " eugonic," as opposed to " dysgonic," 

 the term applied to the bovine bacillus. On glycerin 

 media, the growth tends to become wrinkled ; and on 

 all media becomes pigmented to a greater or less extent. 

 Its effects on animals place it in still greater contrast 

 to the bovine type. 



Calves : subcutaneous injection in neck of 50 mgr. 

 of culture under three weeks old, does not produce pro- 

 gressive tuberculosis, nor does it kill. Only a local lesion 

 results, which later becomes fibrous. In about half the 

 cases, the infection did not extend beyond the nearest glands. 



Rabbits : intravenous injection of o-i mgr. to 1 mgr. 

 of culture causes slowly progressive tuberculosis with 

 limited lesions, and death (for the majority) after three 

 months (thirteen weeks). Intraperitoneally, 1 mgr. ; 

 animal alive after three months. Subcutaneous injection 

 of 1 to 100 mgr. ; animals survived or were killed in 

 94 to 725 days. In certain cases 1 mgr. or o-i mgr. intra- 



