844 PATHOGENIC MICROORGANISMS 



CHOLERA-LIKE SPIRILLA 



The biological group of the spirilla, to which the cholera 

 spirillum belongs, is a large one, numbering probably over a hundred 

 separate species. Most of these are of bacteriological importance 

 chiefly because of the difficulties which they add to the task of 

 differentiation, for while some of them simply bear a morphological 

 resemblance to the true cholera vibrio, others can be distinguished 

 only by their serum reactions and pathogenicity for various animals. 

 Additional difficulty, too, is contributed by the fact that within the 

 group of true cholera organisms occasional variations in agglu- 

 tinability and bacteriolytic reactions may exist. Certain strains, 

 too, the six El Tor cultures isolated by Gottschlich, while in every 

 respect similar to true cholera spirilla, are considered as a separate 

 sub-species by Kraus, 22 because of their ability to produce hemolytic 

 substances, a function lacking in other cholera strains. 



Spirillum Metchnikovl This spirillum was discovered by 

 Gamaleia 23 in the feces and blood of domestic fowl, in which it had 

 caused an intestinal disease. Morphologically and in staining reac- 

 tions it is identical with Spirillum choleraeasiaticse. It possesses a 

 single polar flagellum, and is actively motile. Culturally it is iden- 

 tical with Vibrio cholerae except for slightly more luxuriant growth 

 and more rapid fluidification of gelatin. It gives the cholera-red 

 reaction in pepton media. 



It is differentiated from the cholera vibrio by its power to 

 produce a rapidly fatal septicemia in pigeons after subcutaneous 

 inoculation of minute quantities. 24 It is much more pathogenic for 

 guinea-pigs than the cholera vibrio. It is not subject to lysis or 

 agglutinated by cholera immune sera. 



Spirillum Massaua. This organism was isolated at Massaua by 

 Pasquale 25 in 1891 from the feces of a clinically doubtful case of 

 cholera. Culturally and morphologically it is much like the true 

 cholera vibrio, but in pathogenicity is closer to Spirillum Metchni- 

 kovi, in that small quantities produce septicemia in birds. It pos- 

 sesses four flagella. It does not give a specific serum reaction with 

 cholera immune serum. 



22 Kraus, Kraus and Levaditi, "Handbueh," vol. i. p. 186. 



23 Gamaleia, Ann. de 1'inst. Pasteur, 1883. 

 2 *Pfeiffer und Nocht, Zeit. f. Hyg., vii, 1889. 



25 Pasquale, Giorn, med. de r. escre. ed. B. Marina, Boma, 1891. 



