THE TUBERCULINS 85 



The Tuberculins 



The toxin of the tubercle bacilli (old tuberculin) is prepared by 

 growing the organism for a long period in glycerinized veal broth, 

 after which the flasks are steamed in a sterilizer for an hour or 

 more, and then the bacilli are filtered out through porcelain filters. 

 The filtrate is reduced by boiling to one-tenth of its bulk, and to 

 this .5 percent of carbolic acid is added as a preservative. If 

 this toxin, even in minute doses, is injected under the skin of a 

 tuberculous animal, it acts as a powerful poison. In a few hours, 

 it causes a rapid rise of body temperature, accompanied by nausea 

 and, perhaps, vomiting. About the localized foci of tuberculosis, 

 a vigorous reaction occurs. Around indolent old sores and other 

 lesions there is a tendency to heal by the casting off of necrosed 

 tissues, and the infiltration of the perituberculous area with leu- 

 cocytes. In lupus (tuberculosis of the skin) redness and heat 

 occur about the lesion. This febrile phenomenon following the 

 injection of tuberculin into tuberculous animals is a valuable 

 diagnostic feature toward the recognition of tuberculosis in 

 animals and in man. In 90 percent of cases the reaction is 

 trustworthy. 



Its use in man has been much questioned, as it is thought by 

 some to disseminate the disease from original and confined foci. 

 This, however, has been denied. Many able clinicians use it and 

 recommend it (Osier, Trudeau, Musser). 



Koch's new, or T.R. tuberculin was, like the old, designed by 

 him as a therapeutic agent for the cure of tuberculosis. It is 

 made by pulverizing the bodies of living tubercle bacilli and dis- 

 solving the residuum in an indifferent fluid, centrifuging this and 

 collecting the sediment which is Tuberculin Rest, T.R. The 

 solution above this sediment containing soluble substances from 

 the bacillary bodies is Tuberculin Obers, T.O. It produces a 

 more intense reaction than the old tuberculin. Like the old, it 

 is used in the treatment of lung, bone, laryngeal, and skin tuber- 



