292 BACTERIOLOGY. 



grammes produces in at least 95 per cent, a rise of tem- 

 perature of from 1 to 3 C. The febrile reaction occurs 

 in from twelve to fifteen hours after the injection. Its 

 intensity and duration do not depend upon the extent 

 of the tuberculous lesions, but is even more marked 

 when these are slight than in advanced cases. In non- 

 tuberculous animals no reaction occurs, or one much 

 less than in tuberculous animals, and the results ob- 

 tained on autopsy justify the suspicion that tubercu- 

 losis exists if an elevation of temperature of a degree 

 or more occurs from the subcutaneous injection of the 

 dose mentioned. For these injections the crude old 

 tuberculin is used, which for the convenience of admin- 

 istration is diluted with water. The following are the 

 directions for inspecting herds for tuberculosis : 



(t Inspections should be carried on while the herd is 

 stabled. If it is necessary to stable animals under 

 unusual conditions or among unusual surroundings that 

 make them uneasy and excited the tuberculin test should 

 be postponed until the cattle have become accustomed 

 to the conditions they are subjected to, and then begin 

 with a careful physical examination of each animal. 

 This is essential, because in some severe cases of tuber- 

 culosis, on account of saturation with toxins, no reaction 

 follows the injection of tuberculin, but experience has 

 shown that these cases can be discovered by physical 

 examination. This should include a careful examina- 

 tion of the udder and of the superficial lymphatic glands 

 and auscultation of the lungs. 



" Each animal should be numbered or described in 

 such a way that it can be recognized without difficulty. 

 It is well to number the stalls with chalk and transfer 

 these numbers to the temperature-sheet, so that the 



