58 MAINE AGRICULTURAL EXPERIMENT STATION. 



reacted again January 25, 1895. They were tested February 6, 

 February 22, March n, April 20, June 8 and August 1, and did 

 not react at any of these times. They were killed August 22, 

 1895. The lungs of No. 5 and the lungs and a mediastinal 

 gland of No. 6 contained small cheesy abscesses. 



Dunkard Girl was tested first November 21, 1893, before she 

 was a year old. Up to August, 1895, she had been tested six 

 times without reacting. August 13, 1895, she reacted with a 

 temperature of 107.4. August 29, 1895, she was tested again 

 and reacted with exactly the same maximum temperature, 107.4. 

 During September, 1895, she was tested twice and did not react. 

 October 8, 14 days after the last test in September, she reacted 

 with a maximum temperature of 105. She was tested October 

 19 and October 31, and failed to react. Tested November 20, 

 she reacted with a temperature of 104.8. December 7 she did 

 not react. January 3, 1896, she reacted with a temperature of 

 106.2. From January 3, 1896, to January 13, 1897, when she 

 was tested the last time, she was given eight tests. The longest 

 intervals being one and one-half month, and four and one-half 

 months, but she failed to react after January 3, 1896. January 

 15, 1897, she was killed and tubercular lesions of the right lung 

 and of two mediastinal glands were found. 



August 13, 1895, a two-months-old heifer Kate, was tested 

 and failed to react. February 14, 1896, she was tested again and 

 did react. From that time to November 3, 1896, she was tested 

 eight times at various intervals, and at each time failed to react, 

 and she has not been tested since. 



In considering these cases and others, the records of which are 

 given in the accompanying tables, we notice that, although the 

 animals were all undobtedly tuberculous, out of the 116 tests 

 made, there were 33 reactions and 83 failures. Steer No. 4 did 

 not react at all, but we count the last time he was tested among 

 the failures to react, as the autopsy held twenty-six days later 

 proved that he must have been diseased at the time that test was 

 made. 



Why is it that these animals were sometimes affected by 

 tuberculin and at other times not affected? 



The amount of tuberculin used in making the injections has 

 been uniform for the same stage of maturity, yet the results 



