172 ANNUAL RErORT OF THE Off. Doc. 



During the latter part of the summer of 1910, it was noticed by 

 the superintendent of the farm that lliese two animals aforemen- 

 tioned, were not in the best of condition and were therefore again re- 

 moved frm the herd and kept separate for several months, during 

 which time they continued to lose llesh, coat became rough and cough 

 increased. This action was taken by the superintendent during my 

 absence abroad and upon my return I advised the killing of these 

 two cows. The autopsy revealed extensive tuberculosis of the glands 

 and other organs of both the thoracic and adominal cavities. 



This experience taken in conjunction with a number of otheis 

 that I have had during the past two years, leads me to believe that 

 an animal that has once reacted to the tuberculin test in a positive 

 manner must be considered a tubercular subject no matter what 

 subsequent tests may reveal. It may be, however, that some reactors 

 will live for a number of years following the date of their initial 

 reaction without showing any clinical symptoms of tuberculosis. It 

 is my belief that these two animals, namely Proceda and Francelmar, 

 are responsible for the reinfection of the herd and of the percentage 

 of reactions obtained during the year 1910. 



As aforestated, five animals reacted during this year. One was 

 an animal that had been purchased in New York State since the 

 previous test. Another was an animal that had been purchased by an 

 employee of the farm three or four months prior to the injection 

 of tuberculin. This animal, however, was kept separate from the 

 herd, but the owner was constantly associated with the milch cows 

 as he had a certain number of animals to feed, milk and care for 

 each day. The third animal was one that had been vaccinated with 

 tuberculosis vaccine two years previous, and at the time of test 

 showed an enlargement of the left fore knee joint. The reaction in 

 this animal was not typical, but it was decided to sacrifice the same 

 in order to determine the cause of the enlarged knee. Upon autopsy, 

 it was found that the bursa through which the anterior extensor 

 runs was greatly enlarged, indurated and inflamed. No microscopi- 

 cal lesions of tuberculosis could be found. Miscrocopical examina- 

 tion revealed no tubercle bacilli and guinea pigs inoculated with this 

 material remained healthy for a period of three months, when they 

 were killed, and all organs, membranes, etc., were found normal. 



The remaining two reacting animals had been in the herd for 

 more than two years, and upon autopsy, showed small processive 

 foci of tuberculosis, in the various glands and organs. 



The herd was not again tested for nine months, with the follow- 

 ing results: 



Result of Tuberculin Test, 1911. 



Date of test, January. 



Number of animals tested, 160 



Number of animals reacted, 4 



Percentage of reacting animals, 2.5 



Four other animals which had received several years prior to 

 the test four doses of tirberculosis vaccine, gave rather suspicious 

 reactions and were removed from the herd, though two of them are 

 not included in the above percentage of reactions, for upon autopsy 

 they showed no lesions whatever. 



