CHAPTER XVI 



VIBRIO AND SPIRILLUM 



ViBRiONES are called those bacteria which have the shape 

 of a more or less curved cylindrical rod — comma bacilli, 

 and when after division the two new individuals remain 

 joined end to end they form a characteristic S-shaped mi- 

 crobe. Vibriones elongate and by repeated divisions and 

 the new elements remaining joined end to end produce 

 wavy, spiral, or corkscrewlike filaments or spirilla. Spirilla 

 may be uniform without being composed of jointed commas 

 or they may be composed of separate vibrios. Some 

 species of vibrios form uniform unsegmented spirilla, others 

 may have less tendency to do so or may produce short seg- 

 mented spiral chains. When growing in fluid some species 

 form readily long spirilla apparently showing no segmenta- 

 tion. There exist considerable differences both with regard 

 to the length of the spirals and the amount of curvature, 

 for in some media or in some species the comma bacilli or 

 vibrios form readily well twisted spirals, while in another 

 medium or of another species the spirilla are short, or if 

 long are only slightly wavy. Many of the species of vibrios 

 and spirilla are distinctly motile, and where flagella staining 

 had been applied have been seen to be- possessed of one or 



