i 



The syringe used for injecting the tuber- 

 culin should be first sterilized by boiling in 

 water for 15 ininutes. The syringe needle 

 should be disinfected after each injection. 

 At least two preinjection temperatures 

 should be taken and these temperature read- 

 ings should be made at an interval of not 

 less than two hours. The usual temperature 

 limits in normal cattle are from 101 to 103° 

 F., although both of these limits may be ex- 

 ceeded at times. It is best to exclude ani- 

 mals showing temperatures over 103° F. 

 from the test as well as those in advanced 

 stages of pregnancy. During the test all 

 animals sliould be given good care, be prop- 

 erly fed and comfortably stabled, at the 

 same time the usual course of their daily 

 routine disturbed as little as possible. 



AA'liat Constitutes a Positive Reaction. Sub- 

 cutaneous Test. — A positive temperature re- 

 action consists of a rise in temperature of 

 1.5" F. or more (authorities differ) above 

 the normal temperature, as shown by prein- 

 jection temperatures, and this rise in tem- 

 perature should be maintained for from 2 to 

 6 hours before it drops to normal (tubercu- 

 lin curve). The rise in temperature is usually 

 more or less gradual and begins from the 

 6th to the 12th hour subsequent to the in- 

 jection of tuberculin (delayed reactions be- 

 ginning as late as the 20th hour have been 

 noted) and reaches its height from tlie li'th 

 to 21st hour, gradually returning to normal 

 at the 24th to the 40th hour. Accompanying 

 the temperature reaction a general organic 

 reaction may be shown by some of the re- 

 acting animals. Shivering, loss of appetite 

 and lessening of milk flow may be noted as 

 symptoms of an organic reaction. 



A local reaction at the point of injection 

 (swelling and tenderness) of the tuberculin 



1 



