354 THE BACILLUS OF TUBERCULOSIS 



(a) Take the temperature of each animal to be tested at least 

 twice at intervals of three hours before tuberculin is injected. 



(6) Inject the tuberculin in the evening, preferably between the 

 hours of 6 and 9 P.M. The injection should be made with carefully 

 sterilized hypodermic syringes. The most convenient point for inject- 

 ing is back of the left scapula. Prior to the injection the skin should 

 be washed carefully with a 5 per cent, solution of carbolic acid or 

 other antiseptic. 



(c) The temperature should be taken nine hours after the injection, 

 and temperature measurements repeated at regular intervals of two 

 to three hours until the sixteenth hour after the injection. 



(d) When there is no elevation of temperature at this time (sixteen 

 hours after injection) the examination may be discontinued, but if 

 the temperature shows an upward tendency, measurements must be 

 continued until a distinct reaction is recognized or until the tem- 

 perature begins to fall. 



(e) If the reaction is detected prior to the sixteenth hour the 

 measurements should be continued until the expiration of this 

 period. 



(/) If there is an unusual change of temperature of the stable, 

 or a sudden change in the weather, this fact should be recorded on 

 the report blank. 



(g) If a cow is in a febrile condition tuberculin should not be 

 used, because it would be impossible to determine whether, if a rise 

 in temperature occurred, it was due to the tuberculin or to some 

 transitory illness. 



(Ji) Cows should not be tested within a few days before or after 

 calving, for experience has shown that the result at this time may 

 be'misleading. 



(i) The tuberculin test is not recommended for calves under three 

 months old. 



(j) In old, emaciated animals and in re-tests use twice the usual 

 dose, for these animals are less sensitive. 



(&) Condemned cattle must be removed from the herd and kept 

 away from those that are healthy. 



(/) In making postmortems the carcasses should be thoroughly 

 inspected and all the organs should be examined. 



Reaction after Tuberculin. The characteristic reaction which occurs 

 when an animal affected with tuberculosis receives an injection of 

 good active tuberculin in the proper dose (see above) is the following : 



The temperature begins to rise gradually six to twelve hours 

 after the injection; twelve to twenty-one hours after the injection it 

 reaches its maximum; between the twenty-fourth and fortieth hours 

 it returns to normal. There is, however, during this interval between 

 the twenty-fourth and fortieth hour not infrequently a second but 

 more moderate rise. In rare cases the first rise may begin before 

 the sixth or after the twelfth hour, but these are rather exceptional 



