30 



culin properly prepared does not contain a single living germ. No 

 living matter is introduced when the lympli is injected under the 

 skin, only a solution which contains a substance produced by 

 the growth of the bacillus tuberculosis when cultivated outside of 

 the body. The active principle coming in contact with the tuber- 

 culous tissue sets up an inflammation which produces the febrile 

 disturbance. 



The delicacy of the tuberculin test and the difficulty of detect- 

 ing tuberculosis in cattle by physical examination was well illus- 

 trated in a recent experiment conducted by the writer. 



Thirty-two cows, all in good condition and apparently healthy, 

 were taken for the experiment ; not one showed a well-marked 

 symptom of the disease. They were treated by injecting a given 

 quantity of prepared tuberculin under the skin by the use of a 

 hypodermic syringe. As a result twenty-five gave a " reaction," 

 and at the conclusion of the test all were slaughtered and a careful 

 examination of the carcasses made. Of the thirty-two tested only 

 seven proved to be free, while twenty-five wei'e found diseased. 



Of the twenty -five diseased, twenty-four had very few nodules 

 present, and while in most instances they were in or about the 

 lungs, some were found in the liver or other abdominal organs. 

 In one alone was there found any great number and in this ani- 

 mal they were so situated and were in such a condition that the 

 general health of the cow did not suffer. 



Where tuberculin has been used in herds in which the disease 

 has been known to exist, a similar condition of affairs has usually 

 been found. 



From what we know of tuberculin as a diagnostic agent it is safe 

 to say that it will find its widest application as a medium by which 

 we may extirpate tuberculosis from our herds ; but not by its em- 

 ployment alone in the detection of obscure cases of the disease, 

 but by its employment in connection with thorough renovation and 

 disinfection of our stables. 



To detect and remove the affected animals from a herd by the 

 use of tuberculin and still allow the healthy to remain in an infected 

 stable under conditions where they are sure to contract the disease, 

 would amount to nothing more than to suppress the trouble for a 

 time. 



For this reason pi'incipally it would appear that tuberculin is 

 suitable only for the use of individual farmers who are so situated 

 that they can employ it in connection with other measures which 

 are absolutely essential to insure success in the matter of eradica- 

 tion and suppression of the disease . 



JAS. B. PAIGE, 



Velerinarian. 



