THE CONQUEST OF DISEASE 



tificially for this purpose and the strength of 

 each lot of vaccine had to be tested by inoculat- 

 ing guinea pigs. Yet while these experiments 

 were being made a bill was strongly supported 

 in Congress making it compulsory to give the 

 animals an anesthetic while the experiments 

 were in progress- -that meant to keep the ani- 

 mals under the influence of ether from periods 

 varying from two days to two weeks an ab- 

 surd and impossible thing. 



Tubercu- Tuberculosis is one of the most prevalent 



losis. diseases among animals under domestication. 



Among cows it is especially important because 

 of man's dependence upon them. In all of the 

 great veterinary laboratories studies of this 

 disease among animals are being carried on 

 with the view of finding means to render ani- 

 mals immune or to cure them. For example, 

 Vallee reported at the International Veteri- 

 nary Congress, at The Hague, in September, 

 1909, the results of some of his experiments 

 upon cattle extending over a period of six 

 years. He had used 166 grown cattle and 500 

 calves. His best results were secured by in- 

 travenous inoculation with living tubercle ba- 

 cilli of an attenuated strain which were derived 

 from the horse. He regards the low virulence 



136 



