306 BACTERIA PATHOGENIC TO MAN 



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

 twice, at intervals of three hours, before tuberculin is injected. 



"(ft) Inject the tuberculin in the evening, preferably between the 

 hours of six and nine. The injection should be made with a carefully 

 sterilized hypodermic syringe. The most convenient point for injec- 

 tion 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- 

 or three hours until the sixteenth hour after the injection. 



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

 hours after the 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 temperature 

 begins to fall. 



" (e) If a reaction is detected prior to the sixteenth hour, the measure- 

 ments of temperature 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 of 

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

 illness. 



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

 calving, for experience has shown that the result at these times 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 of tuberculin, for these animals are less sensitive. 



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

 away from those that are healthy. 



"(/) In making post-mortems the carcasses should be thoroughly 

 inspected, and all of the organs should be examined." 



Tuberculin injections are also made in man to reveal a suspected 

 tuberculosis. At first some believed that the irritation aroused in the 

 tuberculous foci by the tuberculin sometimes caused a dissemination of 

 the bacilli and an increase in the disease. When carefully used, how- 

 ever, in suitable cases there is probably no danger. A drawback to 

 its usefulness is that it does not reveal the extent of the disease, nor 

 whether the tuberculosis is active. It is, however, of great value in 

 selected cases, both surgical and medical, where slight tuberculosis is 

 suspected, and yet no decision can be reached. In the small doses 

 advised an absolutely latent infection would probably give no rise of 

 temperature. I quote here Dr. Trudeau upon the use of the test: 



