27 



of the uon reacting animals. There are very naturally many cases iii 

 which the directions are so carelessly followed that the success has 

 only been moderate ; but even in these cases it is not infrequently 

 reported that the owner now recognizes his errors and will correct 

 them. On various large farms where young animals of different 

 ages are kept in separate yards, extraordinarily favorable results 

 have been obtained. In these cases, it may be definitely assured 

 that in a few years the old affected herd will be replaced by entirely 

 healthy animals. I offer the following as an example of experiments 

 conducted according to the Thurebylille method, which has resulted 

 very favorably. In Jan. 1894, on a certain farm the entire herd 

 consisting chiefly of black variegated Jutland cattle was inoculated. 

 One hundred and thirty-nine reacted (82 per cent of the grown 

 animals) 86 were healthy. In Dec. 1894 the entire healthy division, 

 which through the birth of calves had increased during the year to 

 114, was again inoculated. Eight animals reacted, but here in this 

 year the separation was not accomplished carefully enough. Upon 

 repeating the test in May, 1895, the healthy division contained 117 

 head, of which one animal showed a typical, and one a doubtful 

 reaction. At the last test in Nov. 1895, the division then contain- 

 ing 140 head, only one reacted. 



The struggle against bovine tuberculosis must of course be of 

 several years' duration, but it can and must be crowned with victory. 

 In this struggle tuberculin has yielded an invaluable service. Only 

 with the aid of this agent can we determine the actual extent of the 

 disease. On the basis of the tuberculin investigations we are 

 already in position to establish a rational plan of operation, and by 

 this means alone can we retain the advantages gradually won ; but the 

 contest is well worth the pains. The conquest of bovine tuberculosis 

 promises not only large economic profit, but also the annihilation of 

 an important source of human tuberculosis. 



