NON-PATHOGENIC SPIRILLA. 699 



423. SPIRILLUM ft OF WEIBEL. 



Synonym. Vibrio saprophiles ft (Weibel). 



Found in putrefying hay infusion. 



Morphology. Slender, curved rods, of about the thickness of the tubercle 

 bacillus, and averaging 2u in length; the ends are blunt; frequently two 

 elements are united in S-form, but long filaments do not occur; involution 

 forms common. 



Biological Characters. An aerobic, non-liquefying, actively motile 

 spirillum ("vibrio"). Spore formation not determined. Grows rather 

 slowly at the room temperature. Upon gelatin plates the colonies never ex- 

 ceed 0.3 millimetre in diameter; they are spherical, and by transmitted 

 light have a yellowish-brown color. In gelatin stick cultures the growth is 

 similar to that of the preceding speciesSpirillum a. In agar stick cul- 

 tures no growth occurs along the line of puncture; on the surface a cream - 

 like, yellowish-white, viscid layer is formed, which cannot be raised with- 

 out bringing away some of the culture medium. Upon potato a thin 



a 





FIG. 253. FIG. 254. 



FIG. 253. Spirillum y of Weibel. (Weibel.) 

 Fio. 254. Spirillum aureum. (Weibel.) 



shining, varnish-like layer of a dirty brownish-green color and a viscid, 

 dry consistence, which is with difficulty removed by the platinum needle. 



424. SPIRILLUM Y OP WEIBEL. 



Synonym. Vibrio saprophiles y (Weibel). 



Found in the slime deposited in sewers. 



Morphology. Curved rods with round ends, one-half larger than "Vib- 

 rio saprophiles a. " of Weibel ; S-shaped forms are seen, but spiral filaments 

 are rare; involution forms very common in old cultures. 



Biological Characters. -An aerobic, non-liquefying, actively motile spi- 

 rillum ("vibrio"). Spore formation not determined. Grows rather quickly 

 at the room temperature. Upon gelatin plates the deep colonies are white, 

 and at the end of a week about 0.5 millimetre in diameter; under a low 

 power they are seen to be spherical, granular, and orange- colored at the cen- 

 tre, with a sharply defined, pale-yellow marginal zone. The superficial colo- 

 nies are flat, dirty-white, slightly opalescent, with a more prominent white 

 centre ; under a low power the "margin is irregular and notched, the mar- 

 ginal zone white and marked by numerous fine, anastomosing furrows, 

 next to this a light ochre-yellow zone marked by darker lines, and at the 

 centre a golden-brown nucleus marked by delicate, dark, interlacing lines ; 

 at the end of a week the superficial colonies may attain a diameter of five 

 millimetre*. In gelatin stick cultures development occurs along the line of 



