'256 



DISEASES OF THE DOMESTIC ANIMALS 



injection is- made" asepticaliy into the subcutaneous tissue back of 

 the left scapula or into the side of the neck with a syringe previously 

 boiled. The animal should be kept in the stable during the time re- 

 quired for the test and should not be allowed to drink large quan- 

 tities of cold water. Tasteless antipyretics are sometimes' placed 

 fraudulently in the food to prevent rise of temperature. The tem- 

 perature of the animal should be taken at 6 A. M. on the morning- 

 following the injection and from that time every two hours till 

 8 P M. 



A rise of 2° F. is necessary for a positive reaction— that' is, a 

 rise of 2° over the maximum temperature of the animal in the 

 fourteen hour's before the injection. Those animals" in which the 

 temperature does not rise to 103 F. within fifteen or twenty hours" 

 after the injection may be considered non-tuberculous. When the 

 temperature is between 103 F. and 104° F. the test is doubtful 

 and the animal should be re-tested after three months. When the 

 temperature rises gradually to 104 F. or over within fifteen hours" 

 after the injection, the animals may be classed positively tubercu- 

 lous — providing this temperature constitutes a rise of two degrees 

 over the maximum temperature recorded prior to the injection. 



Before admitting- new cows to a herd they should be isolated ' 

 until tested twice with tuberculin without reacting. This is neces- 

 sary because cows may not react in the incubative or latent stage 

 and because previous injection of cows with tuberculin may render 

 them insusceptible to the usual doses. Therefore, after a first test; 

 with negative result, the cows are kept isolated for three months, 

 when a second test is made with three times the first dose of tuber- 

 culin. Milk from these cows may be sold as certified during the" 

 isolation period after the first negative test. 



Old and emaciated animals require' double the ordinary doseof 

 tuberculin, and in all re-tests three times the initial dose should be 

 injected. The average dose of the tuberculin as prepared and 

 diluted for immediate use by the U. S. Government is 2 c.c, repre- 



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