138 PRINCIPLES OF VETERINARY SURGERY 



and staining according to well laid-down rules, which differ 

 somewhat with the particular tissue from which the speci- 

 men is taken. In this method the peculiar behavior of the 

 bacillus in regard to staining and the tenacity of its stain is 

 regarded as sufficient evidence that the microbe at hand is 

 the tubercle bacillus. The fact that relatively large quanti- 

 ties of tissue may contain but few bacilli must always be 

 taken into account. They may escape notice. When sev- 

 eral attempts gi\'e negative results, and when considerable 

 importance is attached to the diagnosis, the second recourse 

 must supplement the microscopic examination. 



2. Animal Inoculation. — The suspected tissues are 

 emulsified and inoculated into a cavy which three weeks 

 later is killed and examined for the tubercle bacillus. The 

 lesions in the center of the lymphatic glands is the most 

 likely place to find them. These specimens are mounted 

 and stained in the usual manner prescribed. 



3. The Tuberculin Test. — This test is the most practi- 

 cal and the most eftectual in veterinary subjects. It is used 

 more particularly in the bovine species. It is the only 

 method by which the occult form can be recognized, and 

 through which the number of affected animals of a given 

 herd can be determined. The preceding tests are not avail- 

 able except when the lesions can be reached, or at the post- 

 mortem examination. 



In this test the temperature curve alone is depended 

 upon. The preliminary and the final examination, after 

 the inoculation with tuberculin, consists exclusively of tak- 

 ing the temperature. The tuberculin is injected into the 

 shoulder after the temperature has been observed at least 

 three times during the twenty-four hours preceding the date 

 of injection, "yet in busy field work one night temperature 

 taken just before injecting rarely fails to give a satisfactory 

 normal as to the standard for the animal." (Law). The 



