260 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



tions had been made. Later on, when they were killed and exam- 

 ined post-mortem, all with the exception of No. 450 were found 

 to have tuberculous lesions directly traceable to the tubercle bacilli 

 injected into the ends of their tails, proving definitely that the 

 strain of tubercle bacillus used was too virulent for the injection 

 of calves in any manner. 



Calf No. 450, after remaining in a tuberculous environment 

 for several years, was found on autopsy to be in excellent condition 

 and entirely free from lesions of tuberculosis. 



On June 20, 1906, the following 5 calves received each a sub- 

 cutaneous injection, immediately above the brush at the end of 

 the tail, of 3 c. c. of a suspension of a virulent human tubercle 

 bacilli. The tubercle culture used was "Boy V," and each cubic 

 centimeter of the suspension represented 0.01 gram of tubercle 

 bacilli. 



Heifer calf No. 449, about 3% months old; Bull calf No. 

 452, about 2 1 /2 months old; Bull calf No. 453, about 2^2 months 

 old ; Bull calf No. 454, about 3 months old ; Heifer calf No. 455, about 

 3 months old. 



With the exception of a slight swelling at the seat of injection, 

 which gradually subsided, the treatment received by the calves 

 caused no visible lesions. Some time after the protective injections 

 were made the calves were exposed to a tuberculous environment, 

 and later on they were killed and examined post-mortem. 



Calves 449 and 453 showed no lesions of tuberculosis as a 

 result of either the protective injections or the exposure. Calves 

 452 and 454 each showed a small tuberculous abscess at the seat 

 of inoculation in the tail and small tuberculous foci in the coccy- 

 geal lymph glands (the lymph glands located near the root of the 

 tail), and no lesions as a result of the exposure to tuberculosis 

 after the protective injections had been made. Calf 455 was found 

 on autopsy to have tuberculous lesions in the coccygeal and phar- 

 yngeal glands, or, in other words, to have contracted tuberculosis 

 both from the protective injection and the subsequent exposure. 



All the tuberculous lesions found were small, but calves 452, 

 454, and 455 show conclusively that the strain of tubercle bacillus 

 injected was too virulent to be used for immunizing purposes. 

 Calves 449, 452, 453, 454 indicate that even a subcutaneous injec- 

 tion of tubercle bacilli can protect against subsequent exposure to 

 a tuberculous environment, and No. 455 shows that a tuberculous 

 process induced by inoculation does not necessarily, in all instances, 

 protect against fresh infection from without, and this is one of the 

 most important facts with which we have to deal in the question 

 of bovo-vaccination. 



On November 14, 1906, the following cattle received each a 

 subcutaneous injection, immediately above the brush at the end 

 of the tail, of 3 c. c. of a suspension of bovine tubercle bacilli. The 

 tubercle culture used was "Bovine III," and each cubic centimeter 

 of suspension was equal to 0.01 gram of tubercle bacilli. 



