308 A MANUAL OF BACTERIOLOGY 



by the mouth than by subcutaneous inoculation. By 

 giving tulase to cows, the milk is said to acquire immu- 

 nising and curative properties which are transmitted to 

 those consuming it. Rosenbach's tuberculin is prepared 

 by growing the tubercle bacillus with the ringworm or- 

 ganism, Friedmann's is derived from a turtle tubercle 

 bacillus. Other tuberculins are also on the market, and 

 any tuberculin may be prepared with a human or with a 

 bovine strain of bacillus. 



Chemical products. The tubercle bacillus produces no 

 extra-cellular toxin. Crookshank and Herroun obtained 

 from glycerin broth cultures of the tubercle bacillus a 

 proteose and an alkaloidal body. The proteose was also 

 obtained from " perlsucht." Both the alkaloid and the pro- 

 teose (from both sources) produced a rise of temperature in 

 tuberculous guinea-pigs, while in healthy animals the former 

 caused a slight, and the latter a marked, fall in temperature. 



De Schweinitz and Dorset x described chemical products 

 isolated from the tubercle bacillus grown in a special 

 glycerin-asparagin mixture. From the bacilli themselves 

 an acid body was isolated, probably teraconic acid, an 

 unsaturated acid of the fatty series. A certain amount 

 of the same body was also obtained from the special culture 

 medium, but only a trace from glycerin broth, in which 

 the bacilli had been cultivated, in the latter case not 

 because it was not formed, but because of the difficulty 

 of isolation. This acid seemed to produce on injection 

 depression of temperature and necrosis of the tissues 

 locally, possessed some immunising power, and may be 

 the substance producing caseation in the tuberculous 

 nodules. The bacilli extracted with hot water yielded an 

 albuminoid, which gave the tuberculin reaction. This 

 they regard as the fever-producing substance. 



1 Med. Journ. N. Y., 1897, July 24, p. 195. Also Fifteenth Annual 

 Rep. Bureau of Animal Industry, U.S. A,, 189C 



