522 STATE BOARD OF AGRICULTURE. 



Nocard, an ardent admirer of tuberculin, says: "Every one admits to- 

 day the exactitude and marvellous precision of the diagnostic indications 

 furnished by tuberculin." 



Grange says: "Tuberculin is now recognized the world over as the most 

 reliable, safe and practical method of diagnosing tuberculosis." Out of 

 849 tested animals he found 107 which reacted. These cattle were cattle 

 generally suspected before the application of the test. Grange says 

 further:' "I have used tuberculin in upwards of a thousand instances 

 in this State (Michigan) during the past two years and have not discovered 

 a case in all these which would impeach the test." 



In the earlier days of testing tuberculin, the per cent, of error due to 

 tuberculin appears greater than in more recent time. The investigators 

 who usually carried out these experiments were trained scientific men. 

 After the test had been applied a careful examination was made of every 

 animal tested and it was usually found that the per cent, of error was 

 not unnoticably small either where the tuberculin failed to detect tubercu- 

 losis or where a rise of temperature occurred, sufficient to condemn the 

 animal, probably from some other source than tuberculin. Still tuberculin 

 must be regarded as an excellent diagnostic inasmuch as it is far supe- 

 rior to any clinical methods now known. 



While the statistics offered by practitioners are interesting and exceed- 

 ingly valuable, they cannot be regarded as accurate or unquestionable, 

 for the practitioners were concerned only in establishing tuberculosis in 

 the cattle they had condemned by the use of tuberculin. It is the best 

 that can be done under the circumstances and I do not impeach their 

 work. The objections 1 would offer to such statistics as truly accurate 

 are: 



1. Tuberculin tests are applied under the assumption that they are 

 infallible. 



2. Such an assumption necessarily leads to inaccuracy. 



3. The condemned animals only are slaughtered for the purpose of 

 examination. 



4. Exact examinations are not always made of the supposed tubercu- 

 lous lesions, if any are found. 



5. The number of tuberculous animals remaining behind because of a 

 failure to react cannot be estimated. 



For these reasons the ordinary reports of tests which involve thousands 

 of animals cannot be regarded as an exact test of tuberculin, and can 

 only be looked upon as a proof of the value of tuberculin. Clinicians' re- 

 ports are never used as a basis to compute the exactness of knowledge; 

 if this were not so, tuberculosis would have long ago been eradicated by 

 reports of cures, testimonials and various remedies. 



In the spring of 1896 Prof. Grange began the work of eradicating tuber- 

 culosis from the college herd and he conscientiously followed up the work 

 till the summer of 1897 when he became dean of the veterinary department 

 of the Detroit Medical College. This work was done by the use of tubercu- 

 lin, and, inasmuch as his report will follow in this bulletin, I am glad to 

 give the methods he employed as stated by him in his report to the Live 

 Stock Sanitary Commission when he was State Veterinarian: "The plan 

 which I have adopted for applying the test is, substantially that which has 

 been recommended by the Bureau of Animal Industry of the Department 

 of Agriculture at Washington, D. C. which suggests that the temperature 



