100 VACCINE AND SERUM THERAPY 



injection is usually from 2° to 4° F. In rare cases 

 the fever curve just described may show variations in 

 that it may begin sooner or much later, and then, 

 particularly in the latter case, reach the maximum at 

 a later hour also. Simultaneously with the thermal 

 reaction, depression and loss of appetite are frequent, 

 and in cows the milk secretion is generally diminished 

 for a few days. In interpreting a tuberculin reaction 

 the following principles are a safe guide to follow. 

 Animals over six months of age may be regarded as 

 tuberculous — (a) if the highest temperature indicated 

 in the course of a typical reaction exceeds the highest 

 recorded temperature before the tuberculin injection 

 by 2*7° F. or more, or if the rise was at least '9° F. 

 and higher than 104° F. ; (b) if the temperature is 

 elevated 1*8° to 2'5° F. or exceeds 103*1° F. with symp- 

 toms of an organic reaction. Calves under six months 

 old must show an increase of temperature over 104*9° 

 or 105° F. to indicate a positive reaction. 



The intensity of the reaction and the extent of the 

 lesions bear no relation to each other, unless this is an 

 inverse one in the sense that extensively tuberculous 

 animals, hence emaciated and weak, usually react 

 with less intensity than robust individuals in which 

 the tuberculous process is in its first stages or more 

 or less localised. 



The animal may be considered free from tuberculosis 

 if the rise of temperature was not more than 2*7° F. 

 and did not exceed 103'1° F., and if the animal showed 

 no organic reaction. Many clinicians, however, con- 



