506 PATHOGENIC SPIRILLA. 



it, after which the color test may be applied. The result of this, in 

 connection with the morphology of the microorganisms forming the 

 film and the character of growth in the gelatin plates, will estab- 

 lish the diagnosis if the cholera spirillum is present in considerable 

 numbers. If but few are present in the original material it may be 

 necessary to make two or more series of plates and bouillon cultures 

 before a pure culture can be obtained and a positive diagnosis made. 



Brieger has succeeded in isolating several toxic ptomaines from 

 cultures of the cholera bacillus, some of which had previously been 

 obtained from other sources cadaverin, putrescin, creatinin, me- 

 thyl-guanidin. In addition to these he obtained two toxic sub- 

 stances not previously known. One of these is a diamin, resembling 

 trimethylenediamin ; it gave rise to cramps and muscular tremor in 

 inoculated animals. The other poison reduced the frequency of the 

 heart's action and the temperature of the body in the animals sub- 

 jected to experiment. In more recent researches made by Brieger 

 and Frankel (1890) a toxalbumin was obtained from cholera cultures 

 which, when injected subcutaneously into guinea-pigs, caused their 

 death in two or three days, but had no effect upon rabbits. 



Pfeiffer has recently (1892) published his extended researches re- 

 lating to the cholera poison. He finds that recent aerobic cultures of 

 the cholera spirillum contain a specific toxic substance which is fatal 

 to guinea-pigs in extremely small doses. This substance stands 

 inclose relation with the bacterial cells and is perhaps an integral 

 part of the same. The spirilla may be killed by chloroform, thymol, 

 or by desiccation without apparent injury to the toxic potency of 

 this substance. It is destroyed, however, by absolute alcohol, by 

 concentrated solutions of neutral salts, and by the boiling tempera- 

 ture, and secondary toxic products are formed which have a similar 

 physiological action but are from ten to twenty times less potent. 



Similar toxic substances were obtained by Pfeiffer from cultures of 

 Finkler-Prior's spirillum and from Spirillum Metschnikovi. The spi- 

 rillum is not found in the blood or in the various organs of individu- 

 als who have succumbed to an attack of cholera, but it is constantly 

 found in the alvine discharges during life and in the contents of the 

 intestine examined immediately after death ; frequently in almost a 

 pure culture in the colorless " rice-water " discharges. It is evident, 

 therefore, that if we accept it as the etiological agent in this disease, 

 the morbid phenomena must be ascribed to the absorption of toxic 

 substances formed during its multiplication in the intestine. In cases 

 which terminated fatally after a very brief sickness Koch found but 

 slight changes in the mucous membrane of the intestine, which was 

 slightly swollen and reddened ; but in more protracted cases the fol- 

 licles and Peyer's patches were reddened around their margins, and 



