VIBRIO CBOLEBM. 353 



I. Vibrio, (F. 0. Miiller, emend. Loffler.) 



Cells short, slightly bent, rigid, comma-shaped, some- 

 times united in screw-like forms, usually only one, excep- 

 tionally two, polar flagella. There are no endospores. 

 According to Hiippe, arthrospores are formed. 



Key to the Recognition of the Most Important 

 "Varieties, i 



1. Motile witliout phosphorescence. 



(a) Gelatin slo-wly liquefied. Mtroso-indol reaction. Yonng 

 gelatin plate colonies coarsely granular. 



(a) Usually not pathogenic for pigeons. Vibrio cholerse (Koch) 



Buchner, page 353. 

 (/3) Very pathogenic for pigeons. Vibrio Metschnikovii Gama- 

 leia, page 366. 

 (J) Gelatin rapidly liquefied. No nitroso-indol reaction. Young 

 gelatin plate cultures finely granular, brownish-yellow. Vibrio Pro- 

 teus Buclmer, page 367. 



(c) Gelatin not liquefied. Vibrio terrigenus Giinther and Vibrio 

 tonsillaris Stephens and Wood Smith (C. B. xis, 929), page 371. 



2. Motile with phosphorescence. Vibrio albensis Lehm. and 

 Nenm., page 370. 



3. Non-motile. (Spirosoma Migula). Vibrio nasalis Weibel, Vib- 

 rio lingualis Weibel, pages 375, 376. 



Vibrio choleras ^ (Koch). Buchner. 



(Plates 47-51.) 



Synonym. — Spirillum cholerse Koch. 

 Common Names. — Comma bacillus, cholera bacillus, 

 " Bacille virgule " of the French. 



Literature. — Petri, der Cholerakurs, Berlin, 1893. It contains all 

 bacteriologio literature up to 1893. Voges has collected critically 139 

 more recent works (C. B. xix, 466). 



Microscopic Appearance. — Bent rods (about 2 ix 

 long, 0.4 /i thick), the ends not lying in the same plane. 

 The bending is often slight, scarcely perceptible; at other 

 times pronounced (51, i, iii), so that they are almost in 



1 Because of the close relationship of the varieties, the brief state- 

 ments in the key can only point toward a diagnosis, and not furnish a 

 complete description. 



^ In the description illustrations of related varieties are also re- 

 ferred to, when similar pictures occur exceptionally in cholera, 

 23 



