7° TOXINS AND ANTITOXINS. 



it 30 to 40 per cent, of glycerin. It possesses all 

 the general reactions of albuminoids. 



Tuberculin is not toxic in the proper sense of 

 the word. Injected in small quantities into the 

 healthy human being * and into healthy animals, it 

 exerts no effect; on the other hand, however, in 

 tubercular organisms, even in incipient stages of 

 the disease, even where it is almost impossible to 

 make a clinical diagnosis, the injection of very small 

 quantities develops a lively and characteristic 

 reaction, f 



Grasset and Vedel consider the tuberculin as an 

 excellent means of diagnosing tuberculosis in man, 

 but in such a case it is necessary to operate with 

 the greatest caution, with very small quantities 

 of the tuberculin, and to feel, in some sort, the 

 sensitiveness of the patient, particularly in the 

 case of children. 



It is chiefly for the diagnosis of tuberculosis in 

 cattle, however, that tuberculin is valuable. 

 Thanks to Nocard, the procedure has to-day become 

 a common practice. The injection of a fairly 

 large dose, 0.3 to 0.4 Gm., according to the size 

 of the animal, causes, in about ten hours or so, 

 if the animal is tuberculous, a strong febrile reac- 



*Koch: Deutsch. Med. Woch., Nov. 13, 1890-1897, No. 14, 

 p. 209. 



t Annal. de I'Instit. Pasteur, v, p. 191; Arch, de la Soc. Biol, 

 de Saint-P4tersbourg, i, p. 213. 



