326 THE TUBERCLE BACILLUS 



1. The animal to be tested is kept quiet and its temperature taken in the 

 rectum the day before as well as on the day on which it is to be tested. 



2. Dilute the tuberculin. 



Crude tuberculin, - - 1 c.c. 



Boiled water containing 0*5 per cent, carbolic acid, - 9 



This solution will not keep and should be newly prepared for each 

 experiment. 



3. With the usual aseptic precautions inoculate the animal sub-cutane- 

 ously in the neck with 3-4 c.c., according to its size, of the diluted tuberculin. 



4. Take the temperature 12 Hours after inoculation and again 16 hours, 

 20 hours and 24 hours after. [Twelve hours is too late. The temperature 

 should be taken 6, 9, 12, 15, 18 ; 24 and finally 36 hours after inoculation.] 



Any animal which during that period shows a rise of temperature of 1*4 C. 

 ought to be regarded as tuberculous. Animals which suffer a minimal rise 

 of temperature (0'5-0'8 C.) are healthy. When the rise of temperature 

 is between O8 and 1'4 C. there is a suspicion of tuberculosis and the animal 

 should be tested again a month later. 



Note. The tuberculin reaction though of great diagnostic value, is not absolutely 

 reliable. In severely infected animals there may be no reaction. On the other 

 hand, a rise of temperature of 1 C. is not sufficient upon which to base a diagnosis. 

 A few cattle which showed a rise of 2 C. were subsequently found to be free from 

 tuberculosis (Arloing, Rodet and Courmont). Infection of the lung with echinococcus 

 is particularly likely to give the temperature reaction in cattle. 



B. In man. Tuberculin has been used in the diagnosis of doubtful cases 

 of the disease in man. 



The inoculation of tuberculin is always attended with a certain amount of 

 danger and very great care must be exercised in its use. In any case the 

 dose injected must never exceed 0*002 gram, and the following solution 

 should be used. 



Crude tuberculin, - 4 c.c. 



Boiled water containing 0'5 per cent, carbolic acid, - - 996 ,, 



One c.c. of this solution contains 0'004 gram of crude tuberculin and not 

 more than a fraction of 1 c.c. should be inoculated. The temperature is 

 taken for 2 or 3 days before the inoculation and every 8 hours for 36 hours 

 afterwards. The part suspected to be infected must be carefully watched, 

 the local reaction being of the greatest importance from the point of view of 

 diagnosis. In patients who have suffered from tuberculosis for a very long 

 time, small doses of tuberculin often produce no temperature reaction 

 (Freymuth). 



As to the amount of tuberculin to be inoculated to obtain a reaction observers 

 differ. There are three methods of using tuberculin for purposes of diagnosis. 



1. Single inoculation. A single dose of 0'5 c.c. of the above solution 

 (0*002 gram of crude tuberculin) is inoculated. This method is not free 

 from danger. 



2. Inoculation of increasing doses. German observers, among whom 

 tuberculin is largely used for the diagnosis of tuberculosis in man, do not 

 hesitate gradually to increase the amount of tuberculin until the dose inocu- 

 lated is very considerable. Generally a dose of 0'5 mg. of crude tuberculin 

 is inoculated deeply into a muscle in the first instance and then gradually 

 increasing doses of 1, 3, 6 and even 10 or 20 mg. every 3 or 4 days until the 

 specific reaction is obtained. 



In soldiers in apparently good health, Franz found that tuberculin in doses of 

 1-3 mg. set up a reaction in about 64 per cent, of the men and when the dose was 

 increased to 10 mg. 96 per cent, reacted. 







