Tuberculosis . 463 



10. If one has shown a distinct reaction but is still rising at 

 the 16th hour, it should be continued till it begins to fall. The 

 typical reaction is one in which the rise and fall are both gradual , 

 and extend over a number of hours. 



n. In recording the temperatures, there should be noted the 

 exact time of each feeding, watering and milking, or any other 

 condition (change of weather), which may in any way affect the 

 heat production or radiation. 



12. In old, emaciated animals and in second or third tests, 

 Pearson uses twice the usual dose of tuberculin or more. 



Tuberculosis Reaction. With slight variations different opera- 

 tors make their estimate of tuberculosis reaction on nearly the 

 same general basis. A rise of 2 F. over the highest temperature 

 of the day or days before, in the absence of any other appreciable 

 cause, and provided that the elevation has followed the tubercu- 

 losis type of gradual rise and fall, is held to condemn. If, how- 

 ever, this rise does not exceed the normal average, if the tem- 

 perature before injection did not exceed ioo° and that after in- 

 jection 102 , the case may well be held in doubt and reserved for 

 re-testing. If, on the contrary, the initial temperature of the 

 animal was 103 , and there was, between the 8th and 16th hours, 

 a gradual typical rise and fall, reaching 104 or a little over, in 

 the absence of any other cause for this, the subject would be con- 

 demned. Cattle having an initial temperature of 103 or above 

 are not favorable subjects for the test, except in the case of 

 calves in which the temperature is normally higher and the re- 

 action must reach a higher point. In all cases of doubt it is well 

 to hold for a second test, unless urgent sanitary considerations 

 demand that a herd should be freed from the infection in short 

 order. Then it may be better to risk a single error, with the 

 concurrence of the owner, than to leave a possible centre of infec- 

 tion in the herd. 



Local swelling in the seat of injection may be charged to lack 

 of antiseptic care, or the presence of septic germs in the system 

 of the animal prior to injection. 



A chill during the period of reaction is not uncommon, especi- 

 ally in cold weather, or in a draught of cold air. The coat may 

 stare along the spine in patches, or generally, tremors may be 

 seen on the body or limbs, and a clammy coldness invades the 



