EFFECTS OF TUBERCULIN. 57 



During the next three years she was tested six times at intervals 

 varying from twelve days to seven months and nineteen days, 

 and she did not react until the last time she was tested, April 

 2, 1895, when she underwent what might be called a typical 

 reaction with a maximum temperature of 106.3. 



This case compels us to one of four conclusions: Either the 

 test made in June, 1892, was misleading and the cow was not 

 tuberculous at that time, or she recovered and later, in 1895, con- 

 tracted the disease again; or she was diseased from June, 1892, 

 to May, 1895, and repeated tests with tuberculin failed to reveal 

 the fact; or the tuberculin injected in June, 1892, rendered her 

 so tolerant of the drug that the tuberculin injected a little more 

 than a year later had no effect. A few days before this cow was 

 tested the last time, her udder was badly bruised — probably by 

 the cow next to her stepping on it. For a time under the usual 

 treatment she seemed to be making a good recovery from the 

 injury and then steadily and rapidly grew worse. The swelling 

 extended to the other quarter of the uddder on the same side, 

 she developed a cough and was rapidly losing strength and 

 flesh when she was killed, May 7, 1896. The autopsy revealed 

 tuberculosis involving nearly all of one side of the udder, quite 

 an area of one lung, the inguinal and mediastinal and many of 

 the mesenteric lymphatic glands. There was no doubt but the 

 disease was making rapid progress. 



Another case of some interest is a nineteen months old steer 

 (No. 4) that had been tested three times with intervals of seven 

 and one-half and four and one-half months. The last test was 

 made twenty-six days before the autopsy and although the 

 highest temperature observed at any test was 103, the autopsy 

 revealed tuberculosis involving one mediastinal gland and a 

 small area in the right lung. In both localities the tubercular 

 tissue had undergone cheesy degeneration to such an extent 

 as to leave no room for the idea that the disease was contracted 

 after the last test was made only twenty-six days before. 



Cows Xos. 5 and 6, were small, grade cows, related to each 

 other and almost identical in appearance. They were always 

 tested the same day and the results were similar to a remark- 

 able degree. When first tested, August 17, 1894, neither 

 reacted. Tested again January 8, 1895, both reacted, and both 

 5 



