104 TAXONOMY 



cient reasons into lower and higher bacteria, or what are 

 termed by Fischer, Haplobacteria and Trichobacteria. Migula 

 divides all bacteria into two orders: the Eubacteria, or true 

 bacteria, and the Thiobacteria, or sulphur bacteria. Under 

 the Eubacteria, Migula places four families, viz. : Coccaceae, 

 Bacteriaceae, Spirillaceae, and Chlamydobacteriaceae. We 

 believe that a simpler arrangement can be made by placing the 

 families Coccaceae, Bacteriaceae, and Spirillaceae under the 

 suborder of the Haplobacterinae (Fischer) or lower bacteria, 

 and the Chlamydobacteriaceae under the suborder Trichobac- 

 teriae (Fischer) or higher bacteria. The various genera in 

 these families as given by Migula are not changed. 



There are many species of bacteria which possess definite, 

 while others possess variable, characteristics. It is possible 

 to place them in definite genera and to constitute distinct 

 species. It should be remembered, however, that there is un- 

 der certain conditions a striking similarity in form and physi- 

 ological activity among different species of bacteria. For 

 example, certain bacilli are so short that they appear at times 

 to be cocci. It will be easily, seen, therefore, that there is 

 always difficulty in the classification of some organisms. The 

 best classification can be made only when all the various 

 species of bacteria are subjected, as nearly as possible, to the 

 same conditions of temperature, light, gaseous environment, 

 food, etc. 



Classification of Migula (Modified). The bacteria are phy- 

 cochrome-free schizomycetous plants which divide in one, 



