292 BACTERIOLOGY. 
grammes produces in at least 95 per cent. a rise of tem- 
perature of from 1° to 8° 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 : 
‘“ 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 
