THE BIOLOGY OF BACTERIA 



VEGETABLE KINGDOM. 



Thallophyta. 



[ = The lowest forms 

 of vegetable life. No 

 differentiation into 

 root, stem, or leaf.] 

 I 



Muscineae. 



I I 



Pteridophyta. Phanerogam ia. 



Algae. 



[= Chlorophyll 

 present.] 



Fungi. 



[ = No Chlorophyll.] 



Hymenomycetes. Hyphomycetes. Blastoraycetes. Schizomycetes 

 (Mushrooms, etc.) (Moulds.) (Yeasts, etc.) [ = multiplication by cell 



division or by spores] 



or 

 Bacteria. 



Ml) Coccacese ;; r( 

 cells. 



(2) Bacteriacese 



and threads. 



(3) Leptotrichese. 



(4) Cladotrichese. 



* Migula has suggested that the Schizomycetes should be subdivided into Coccacece, Bacteriacecv, Spirillac 

 (spirilla, spirochreta), Chlamydobacteriacece (Streptothrix, Crenothrix, Cladothrix), and Ikggiatoa. 



Morphology: Structure and Form 



Having now located micro-organisms in the economy of nature, 

 we may proceed to describe their subdivisions and form. For 

 practical convenience rather than theoretical accuracy, we may accept 

 the simple division of the family of bacteria into three chief forms, 

 viz. : 



( (1) Round cell form coccus. 

 Lower Bacteria-! (2) Eod form 'bacillus. 



( (3) Thread form spirillum. 

 Higher Bacteria Leptothrix, Streptothrix, Cladothrix, etc. 



A classification dependent as this is upon the form alone is not by 

 any means ideal, for it ignores all the complicated functions of 

 bacteria, but it is, as we have said, practically convenient. 



1. The Coccus. This is the group of round cells. They vary in 

 size as regards species, and as regards the conditions, artificial or 

 natural, under which they have been grown. Some are less than 

 2- WOTF f an i ncn m diameter ; others are half as large again, if the 

 word large may be used to describe such minute objects. No regular 

 standard can be laid down as reliable with regard to their size. 

 Hence the subdivisions of the cocci are dependent not upon the 

 individual elements so much as upon the relation of those elements to 

 each other. A simple round cell of approximately the size already 

 named is termed a microcowus (jumcpos, small). Certain species of 



