174 Biological Therapy 



after the measuring of temperature. Occasionally it is ad- 

 visable to limit the quantity of concentrated food given 

 animals under test. This is especially true if large quantities 

 of that kind of food are allowed. 



3. A careful physical examination of each animal 

 should be made before or during the application of the test. 



4. During the period immediately before the injection 

 of tuberculin each animal's temperature should be taken at 

 least three times at not less than two-hour intervals. Care 

 should be taken to let the thermometers remain inserted for 

 a sufficient length of time to insure correct reading. Animals 

 showing evidence of any acute disease or condition or show- 

 ing extensive pus formations should not be injected with 

 tuberculin. Any animal showing pronounced abnormal 

 preliminary temperatures likewise should not receive the 

 tuberculin test. Inquiry concerning the history of the herd 

 should be made, and it should be ascertained, if possible, 

 whether any animal in the herd has ever given a positive 

 reaction to tuberculin, the number of tuberculin tests applied 

 to the herd previously and also whether any cattle in the 

 herd have been treated at any time in any other manner 

 with tuberculin. The information thus obtained should be 

 used in determining the method to be employed in the tuber- 

 culin testing of the herd. 



5. The hypodermic syringes and needles should be dis- 

 infected before testing any herd with tuberculin. Before 

 being used for the injection of each animal, needles should be 

 washed in a disinfectant solution. A five per cent solution 

 of carbolic acid is suitable for sterilizing the instruments. 

 Open bottles of tuberculin should be protected from contam- 

 ination. Thermometers should be sterilized before the tem- 

 perature is taken, and should be dipped in a disinfectant 

 solution before and after each reading. 



6. For cattle which are apparently healthy, and wHiich 

 have not been injected with tuberculin within a period of at 

 least 60 days, the dose of tuberculin prepared by the Bureau 

 of Animal Industry is as follows : 



Two mils for calves ranging from six 

 months to one year of age. 



Four mils for cattle more than one year old 

 to maturity. 



Older animals or animals clinically sus- 

 picious may receive a larger dose. 



