SPIRILLUM TYROGENUM 159 



On Potato at room temperature a shiny, greyish-yellow, glistening layer 

 occurs, soon spreading over the surface of the potato. (The vibrio 

 of Asiatic cholera exhibits no growth on potato at room temperature.) The 

 cultures give off a strong putrefactive odour, and in media containing 

 sugar produce an acid reaction. 



Pathogenesis. Pathogenic for guinea-pigs when injected into the 

 stomach previously rendered alkaline with soda. 



SPIRILLUM TYROGENUM. 



(Vibrio Deneke.) 



This vibrio was obtained by Deneke from old cheese. 



Microscopical Appearances. Curved rods and long spiral fila- 

 ments resembling the cholera vibrio, the diameter of the commas being 

 uniform throughout, so that it more closely resembles the cholera vibrio 

 than does that of Finkler and Prior. 



Motility. Strongly motile, possessing a single flagellum at one end 

 (Monotricha). 



Staining Reactions. Stains with the usual aniline dyes, best with 

 an aqueous solution of fuchsin. 



Biological Characters. Aerobic and facultative anaerobic lique- 

 fying vibrio, growing at ordinary room temperature more rapid than the 

 cholera vibrio, but not so rapid as the vibrio proteus of Finkler and 

 Prior. 



On Gelatine Plates small punctiform colonies develop, which on the 

 second day are about the size of a pinhead and have a yellowish colour ; 

 examined under a low power they appear coarsely granular, yellowish- 

 green coloured in the centre and paler towards the margins ; funnel- 

 shaped cavities are formed when liquefaction commences, 



In Gelatine Stab Cultures liquefaction takes place along the inoculation 

 track, the vibrios sinking to the bottom of the medium in a mass, while 

 a thin yellowish layer forms upon the surface ; complete liquefaction takes 

 place in about two weeks. 



On Agar a yellowish-white coating is formed on the surface. 



Blood Serum is quickly liquefied. 



In Bouillon or Peptone Solution the nitroso-indol reaction is awanting. 



Pathogenesis. Fifteen guinea-pigs were treated with soda and 

 tincture of opium, the same as Koch's method with Asiatic cholera, and 

 the vibrio introduced into the intestines, but only three of the infected 

 animals succumbed. 



