106 BACTERIAL POISONS. 



sterilization decreased the toxicity of the fluid. From these 

 facts Cantani conckided that the poisonous principle is 

 volatile, but the eifect of high or prolonged heat in dimin- 

 ishing the toxicity was more probably due to its destructive 

 effect on the poisonous proteids. 



Cantani also observed that the blood of those sick with 

 cholera is acid : this has been confirmed by Strauss by 

 the examination of the blood directly after death ; and 

 Ahrend found lactic acid in the strongly acid urine of a 

 cholera patient. 



NicATi and Rietsch produced fatal effects in dogs by 

 injecting cultures, from which all germs had been removed 

 by filtration, into the bloodvessels. Later, the same inves- 

 tigators obtained from old bouillon cultures containing 

 peptone a poisonous base. Ermengen also showed that 

 cultures after filtration through a Chamberland filter are 

 poisonous. 



Klebs has attemped to answer experimentally the ques- 

 tion. In what way does the cholera germ prove harmful ? 

 Cultures of the bacillus in fish preparations were acidified, 

 filtered, the :filtrate evaporated on the water-bath, the residue 

 taken up -with alcohol and precipitated with platinum chlo- 

 ride. The platinum was removed with hydrogen sulphide, 

 and the crystalline residue obtained on evaporation was 

 dissolved in water and injected intravenously into rabbits. 

 Muscular contractions were induced. Death followed in 

 one animal, which, in addition to the above treatment, 

 received an injection of a non-sterilized culture. In this 

 case there was observed an extensive calcification of the 

 epithelium of the uriniferous tubules. Klebs believes this 

 change in the kidney to be induced by the chemical poison, 

 and from this standpoint he explains the symptoms of 

 cholera as follows : The cyanosis is a consequence of ai'te- 

 rial contraction, the first effect of the poison. The mus- 

 cular contractions also result from the action of the poison. 

 The serous exudate into the intestines follows upon epithe- 

 lial necrosis. Anuria and the subsequent symptoms appear 

 when the formation and absorption of the poison become 

 greatest. 



