No. 4.] CATTLE COMMISSIONERS' EEPORT. 397 



York State Board of Health, and J. J. McKensie of the Pro- 

 vincial Board of Health. The experiment stations of Canada, 

 Vermont, New York, New Jersey, Pennsylvania, Virginia, Wis- 

 consin and Minnesota have used it with convincing results. 

 Quotations might be made from the reports of many investiga- 

 tors, American and foreign ; but the following, taken from the 

 Vermont Bulletin No. 42, may suffice : — 



' ' AVe shall now stop publishing reports on tuberculin in the 

 Berlin Veterinary Weekly unless they contain some new facts 

 or views. Since the publication of the reports of the extensive 

 experiments of the royal health office, we may regard the ques- 

 tion of the value of tuberculin in the diagnosis of tuberculosis 

 of cattle as settled. The proof which has been presented to our 

 readers is more than sufficient. The results are absolute and 

 gratifying, and show that tuberculin is a reliable agent for de- 

 termining the presence of tuberculosis in cattle." 



It will therefore readily be seen that the use of tuberculin as 

 a means of detecting the existence of tuberculosis in cattle has 

 become general, notwithstanding the fact that for the purpose 

 for which it was originally intended it has fallen into entire 

 disuse. 



It is only comparatively a few years (1882) since the fact was 

 discovered and generally accepted that tuberculosis — that is, 

 consumption — is a contagious disease, and that it is due in all 

 cases to the presence of a particular germ, the bacillus tuber- 

 culosis. 



Among people who have not given the matter of this disease 

 any special study or attention, there is a misapprehension to a 

 greater or less extent as to the nature of the disease and its con- 

 tagion. In order that a given subject may become afflicted with 

 tuberculosis, generally speaking, there must be two conditions ; 

 first, the presence of the bacillus ; and, second, a receptive con- 

 dition of the individual. No matter what the condition of the 

 individual is, it is impossible to have the disease unless the germ 

 is present. Practically speaking, it is also true that in a great 

 majority of cases the presence of the germ will not produce the 

 disease unless the subject is in a condition which is favorable to 

 the orermination of the bacillus. Because of the existence of 

 the germ, we are enabled to determine, by the use of tubercu- 

 lin, the presence of the disease in the individual. 



