SPIRILLA RESEMBLING CHOLERA SPIRILLUM. 423 



cultivated from other sources, and which more or less 

 closely resemble it. 



Other Spirilla Resembling the Cholera Organism. 

 These have been chiefly obtained either from water con- 

 taminated by sewage or from the intestinal discharge in 

 cases with choleraic symptoms. Some of them differ so 

 widely in their cultural and other characters (some, for 

 example, are phosphorescent) that no one would hesitate to 

 classify them as distinct species. Others, however, closely 

 resemble the cholera organism. 



The vibrio berolinensis, cultivated by Neisser from Berlin sewage 

 water, differs from the cholera organism only in the appearance of its 

 colonies in gelatine plates, its weak pathogenic action, and its giving a 

 negative result with Pfeiffer's test. It, however, gives the cholera-red 

 reaction. The vibrio Danubicus, cultivated by Heider from canal 

 water, also differs in the appearance of its colonies in plates, and also 

 reacts negatively to Pfeiffer's test ; in most respects it closely resembles 

 the cholera organism. Another spirillum (v. Ivanoff} was cultivated 

 by Ivanoff from the stools of a typhoid patient after these had been 

 diluted with water. This organism differed somewhat in the appear- 

 ance of its colonies and in its great tendency to grow out in the form 

 of long threads, but Pfeiffer found that it reacted to his test in the 

 same way as the cholera organism, and he considered that it was really 

 a variety of the cholera organism. No spirilla could be found micro- 

 scopically in the stools in this case, and Pfeiffer is of the opinion that 

 the organism gained entrance accidentally. These examples will show 

 how differences of opinion, even amongst authorities, might arise as to 

 whether a certain spirillum were really the cholera organism or a 

 distinct species resembling it. 



A few examples may also be given of organisms cul- 

 tivated from cases in which cholera- like symptoms were 

 present. 



The vibrio of Massowah was cultivated by Pasquale from a case 

 during a small epidemic of cholera. This organism so closely re- 

 sembles Koch's spirillum that it was accepted by several authorities as 

 the true cholera organism, and, as already stated, Metchnikoff pro- 

 duced by it cholera symptoms in the human subject, and also the 

 cholera-like disease in young rabbits. It possesses four flagella, has a 

 high degree of virulence, producing septicaemia both in guinea-pigs 

 and pigeons, and its colonies in plates differ somewhat from the 

 cholera organism. Moreover, it reacts negatively to Pfeiffer's test. 



