DIAGNOSTIC INOCULATION. 221 



jection temperature is at least 1° C. [1.8° F.] are regarded as 

 tuberculous. - 



b. In calves under 6 months of age a rise of temperature 

 exceeding 40° C. (104° F.) after injection of the tuberculin, 

 provided the difference between the highest pre- and post- 

 .injuction temperatures is at least 1° C. (1.8° F.) indicates 

 the existence of tuberculosis. 



The International Veterinary Cragress of Budapest has 

 accepted the following interpretation of the results of a tuber- 

 culin test : 



1. A post-injection temperature exceeding 40° C. [104° 

 F.], provided the temperature at the time of injection did not 

 exceed 39.5° C. (103.1° F.), is to be regarded as a positive 

 reaction. 



If the pre-injection temperatures of cattle exceed 39.5° C. 

 C. [103.1° F.] and 40° C. [ 104.0 °F.] the results are to be 

 regarded as doubtful and to be considered upon their own 

 merits. 



If the pre-injection temperatures of cattle exceed 39 :5° C. 

 [103.1° F.], or if those of calves less than six months of age 

 exceed 40° C. [104.0° F.], the tuberculin test should be made 

 at a later date. 



Reliability. The tuberculin test cannot be regarded 

 as absolutely infallible. About 90% of the tuberculous ani- 

 mals give a reaction. Animals in advanced stages of the dis- 

 ease frequently do not react As a rule, however, a physical 

 examination of such animals reveals symptoms which, when 

 considered alone, would at least awaken suspicion as to the 

 existence of the disease. Only a small per cent, of the react- 

 ing animals is found to be free from tuberculosis. Neves- 

 theless, tuberculin is the best diagnos- 

 ticum in our possession. 



Inoculation of experimental animals. The milk of 

 tuberculous cows contains tubercle bacilli when the udder is 

 affected with tubercular processes, and also in some cases 



