

WHAT ARE BACTERIA ? 43 



The genus vibrio consists of spiral filaments which break 

 up into short fragments. 



The spirillum consists of longer filaments that have a 

 helicoid arrangement. 



The spirochaete, of greater length, are spirilla with more 

 numerous turns of the spiral. 



Micrococci, arranged in zoogloea masses and held together 

 by a thick layer of gelatinous material, he called ascococcus ; 

 when held together, but without or with less of this gelatinous 

 material, he gave them the name of punctula. 



Bacteria united by this gelatinous material are called 

 ascobacteria ; without the gelatinous envelope, polybacteria ; 

 bacteria in the form of spiral threads, and massed together, 

 form the myconostoc. 



These bacteria are again divided according to their pro- 

 perties of forming colouring matter, chromogenes ; of setting 

 up fermentation, the zymogenes ; and of giving rise to 

 disease in animals or plants, the pathogenes. 



He gave a further classification based on the mode of 

 division of the primary cells : 



1. The bacteria in which the division takes place in one 

 axis only. This includes micrococcus, bacterium, bacillus, 

 leptothrix, crenothrix, cladothrix, vibrio, spirillum, spiro- 

 chaete, ascococcus, punctula, ascobacteria, polybacteria, and 

 myconostoc. 



2. The meristae, in which a membranous thallus divides 

 in two directions but on one plane only, giving rise to the 

 formation of characteristic tetrads. 



3. The sarcinae, in which there is division in three direc- 

 tions, so that the resulting masses always remain cubical in 

 form. 



Zopfs classification rests (Fliigge, " Etiology of Infective 

 Diseases," p. 180) on the doctrine of pleomorphism, which 

 cannot be accepted as in any way proved except in the case 

 of a few well-known non-pathogenic forms ; but his classifica- 

 tion maybe accepted as a basis from which to work in bring- 

 ing proof or disproof of the theory of pleomorphism, al- 

 though it is not at present, at any rate, founded on a large 

 number of facts. 



Zopf, who has studied most carefully the subject of pleo- 

 morphism, holds that several forms may occur in the cycle 



