098 NON-PATHOGENIC SPIRILLA. 



thrax bacillus, and two to five times as long as thick ; the amount of curva- 

 ture varies considerably, from nearly straight to semicircular, and short rods 

 may be quite straight. In preparations from agar or gelatin cultures long, 

 closely wound spiral filaments are sometimes seen, or the filaments may be 

 wavy or made up of curved segments. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, non-motile spirillum. Grows slowly at the room temperature 

 better at 37 C. Spore formation not determined. Upon gelatin plates, at 

 the room temperature, grows very slowly ; by the fifth day the colonies may 

 have a diameter of 0.3 millimetre, and finally of 0.6 millimetre at the out- 

 side; under a low power they are seen to be finely granular, and yellowish- 

 brown by transmitted light ; they are spherical in form, with sharply defined 

 margins. In gelatin stick cultures a delicate, veil-like growth is seen along 

 the track of the needle ; no growth upon the surface. Upon the surface of 

 agar a dirty- white, slimy layer is developed at 37 C. No growth upon po- 

 tato. 



422. SPIRILLUM a OF WEIBEL. 



Synonym. Vibrio saprophiles a (Weibel). 

 Found in putrefying hay infusion and in slime from sewers. 

 Morphology. Curved rods, with pointed ends, about 0.6 n thick at the 

 centre, and averaging 3 /* in length ; often two are united in S-form longer 



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~'- t'&i?je~' 



FIG. 251. FIG. 252. 



FIG. 251. Spirillum of Weibel. (Weibel.) 

 FIG. 252. Spirillum ft of Weibel. (Weibel.) 



chains are not common; grow out into spiral filaments; involution forms 

 common. 



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

 spirillum. Grows rather slowly at the room temperature. Spore formation 

 not determined. Potato cultures give off a strong odor of ammonia. Upon 

 gelatin plates the deep colonies, by the third day, are from 0.2 to 0.3 milli- 

 metre in diameter; later they may attain a diameter of 0.6 millimetre; 

 under a low power they are seen to be spherical and yellowish-brown in 

 color ; the opaque centre is surrounded by concentric rings. The superficial 

 colonies are flat white or yellowish discs, irregular in outline, with a finely 

 granular structure ; the centre is greenish-yellow and opaque, and the color 

 fades out toward the periphery; at the end of a week they may attain a dia- 

 meter of two millimetres. In gelatin stick cultures a veil-like, white growth 

 is seen along the line of puncture; later this has a dirty yellowish-red color ; 

 upon the surface a whitish layer gradually extends from the point of punc- 

 ture, and beyond this a transparent, whitish film covers the surface. Upon 

 the surface of agar a cream-like, yellowish-white layer is developed, and 

 the agar beneath is clouded to a depth of one to two millimetres. Upon po- 

 tato, at the end of twodays, an abundant slimy layer is developed; this lias 

 a yellowish-red to chocolate-brown color, and resembles the growth of the 

 bacillus of glanders. 



