CHRONIC INFECTIOUS DISEASES 99 



advanced stages of tuberculosis, and where all the 

 cells of the body are presumably soaked with the 

 tubercle bacillus poisons, often fail to react to the 

 injection of tuberculin. 



Methods of Administering Tuberculin as a Diagnostic 

 Agent: (1) Subcutaneous Injection, — This is the 

 method most frequently used in this country. The 

 ordinary dose of tuberculin for subcutaneous use is : 

 adult cattle, 30 to 60 minims, according to the size ; 

 yearlings, 20 to 30 minims ; calves under six months, 

 10 to 15 minims. The injection is made into the 

 loose skin on the side of the neck, the seat of injection 

 having been previously clipped and washed with an 

 antiseptic. The animals to be tested should be under 

 normal conditions as to feeding, housing, etc. Their 

 temperature should be taken before the injection is 

 made, and animals showing a temperature of 2*5° 

 above normal should be left until the normal 

 temperature is regained. 



The characteristic thermal reaction for tuberculosis 

 consists in a gradual rise of temperature beginning 

 from the sixth to the twelfth hour after subcutaneous 

 injection of the tuberculin, reaching its maximum 

 from the twelfth to the eighteenth hour, thereupon 

 falling with slight interruptions until the normal is 

 reached. After injections the temperature should be 

 taken at the ninth, twelfth, fifteenth, and eighteenth 



4 



hour. 



The difference between the maximum temperature 

 after injection and the temperature recorded before 



