THE TUBERCULIN TEST 383 



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It has been shown that man is susceptible to the bovine type of 

 tuberculosis and that the organism often is found in market milk, 

 and Rosenau estimates that probably 7 per cent, of the cases of 

 tuberculosis thus have their origin. The significance of these 

 figures becomes apparent when we realize that 160,000 individuals 

 die each year in the United States of this disease, and 11,200 would 

 get their infection from milk. 



This is a needless loss of human life, for the information now 

 available is sufficient to prevent every one of these cases if milk be 

 obtained only from cows which have given negative tuberculin 

 tests. 



The Tuberculin Test. This reaction should be applied to all cows 

 and is carried out as follows : 



" Inspections should be carried on while the herd is stabled. If it 

 is necessary to stable animals under unusual conditions or among 

 surroundings that make them uneasy and excited, the tuberculin 

 test should be postponed until the cattle have become accustomed 

 to the new conditions. The inspection should begin with careful 

 physical examination of each animal. This is essential, because in 

 some severe cases of tuberculosis no reaction follows the injection 

 of tuberculin on account of saturation with toxins, but experience 

 has shown that these cases can be discovered by physical examina- 

 tion. The latter should include a careful examination of the udder 

 and of the superficial lymphatic glands and auscultation of the 

 lungs. 



"Each animal should be numbered or described in such a way 

 that it can be recognized without difficulty. It is well to number 

 the stalls with chalk and transfer these numbers to the transfer 

 sheet, so that the temperature of each animal can be recorded in 

 its appropriate place without danger of confusion. The following 

 procedure has been used extensively and has given excellent results: 



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

 twice at intervals of three hours before tuberculin is injected. 



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

 the hours of 6 and 9 P.M. The injection should be made with care- 

 fully sterilized hypodermic syringes. The most convenient point 

 for injecting is back of the left scapula. Prior to the injection the 

 skin should be washed carefully with a 5 per cent, solution of car- 

 bolic acid or other antiseptic. 



(c) "The temperature should be taken nine hours after the injec- 

 tion, 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 temperature begins to fall. 



