THE TUBERCULIN TEST. I59 



ful, accurate and observing-. The cattle must not be excited or 

 worried in any way but kept as quiet as possible during the whole 

 test. If the whole stable or any portion of it be much warmer 

 on the second day, than on the first, note should be made of the 

 fact and it should be considered in making the diagnosis in doubt- 

 ful cases. 



Cattle that show high temperatures during period (A) should 

 ordinarily be released from test, except in case of heavily pregnant 

 cows. These may be tested, if carefully handled — up to within 

 two weeks of calving. It is always possible that an animal may 

 show normal temperature during (A) and then be feverish from 

 causes not connected with the test dviring ( B). This rarely occurs 

 but the possibility must be borne in mind. 



On the other hand a large quantity of very cold water may 

 reduce the temperature one or even two degrees at a critical time 

 in a low reaction. 



Importance to breeders. — The value of the test to breeders 

 lies in the fact that it enables them to know whether their cattle 

 are free from tuberculosis, and it enables them to free their herds 

 and put them on a sound and healthy basis in case they are dis- 

 eased. 



Diagnosis is made mainly upon the fever reaction: i. e., if 

 the temperature rises between 8 and 20 hours after the injection 

 2 degrees or more above the normal range, as shown by compari- 

 son of the (A) and (B) temperatures and careless errors have 

 been avoided, it is safe to diagnose tuberculosis. A rise of 1.5 to 

 2 degrees may be called suspicious and the animal held for future 

 retest. 



The reaction. — A typical reaction is one wherein there is 

 gradual rise and gradual decline. Very abrupt changes should 

 be verified with a different thermometer. When the first (B) 

 temperature is not taken until eight or ten hours after injection, 

 there may be a gradual rise and a maximum reached before this 

 first (B) temperature is taken. One or two high temperatures 

 during (B) with the others normal or nearly so, should not be 

 considered as more than doubtful or suspicious. 



Animals that react sometimes show diarrhea and a local swell- 

 ing at the site of injection. 



