72 MORPHOLOGY OF THE BACTERIA. 



The spherobacteria include only the genus Mi- 

 crococcus. 



g. Micrococcus, Cohn (Hallier emend. — Micro- 

 sphceria, Cohn, ante). 



Cells colorless, or scarcely colored, very small, 

 globular or oval, forming by transverse division 

 filaments of two or several articles, in form of 

 chaplet, or united in numerous cellular families, 

 or in gelatinous masses, all deprived of move- 

 ment. 



The species are divided into three physio- 

 logical groups : — 



a. M. Chromogenes. 



b. M. Zymogenes. 

 o. M. Pathogenes. 



Section (a) : Micrococcus Chromogenes. 



The pigmentary bacteria grow in the state 

 of Zooglcea upon the surface of the substances 

 which furnish them with nutriment. They are 

 always alkaline ; all are avid of oxygen ; their 

 morphological characters are identical, and one 

 can only distinguish them by their different 

 coloring properties. 



According to Cohn, they are veritable spe- 

 cies ; for 1. Their pigments offer the greatest 

 diversity as to chemical action and by spectro- 

 scopic analysis, etc. ; 2. Each species cultivated 

 in the most diverse media produces always the 

 same coloring matter. 



