558 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 in 1892 published his extended researches relating 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 in close rela- 

 tion with the bacterial cells and is perhaps an integral part of the 

 same. The spirilla may be killed by chloroform, thymol, or by desi- 

 cation without apparent injury to the toxic potency of this sub- 

 stance. It is destroyed, however, by absolute alcohol, by concen- 

 trated solutions of neutral salts, and by the boiling temperature, and 

 secondary toxic products are formed which have a similar physio- 

 logical 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 spirillum is not found in the blood or in the various organs of 

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

 constantly found in the alvine discharges during life and in the con- 

 tents 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 

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



