CLASSIFICATION OF ANAEROBIC BACTERIA 531 



three or four spores may occur in a rod which has remained 

 undivided. In fact the only fixed morphological character to 

 be noted is the shape of the spores, which, so far as I know, in 

 this species everywhere remains oval. This is the sole morpho- 

 logical character that was noted in my anaerobic studies that 

 cannot be assailed as inconstant, yet the shape of the spore is a 

 character that has been consistently overlooked by classifying 

 morphologists, who have chosen instead the extremely variable 

 one of spore-position. 



The size of the rod has not been mentioned by most classifiers. 

 In general the sporulating rods are larger than the non-sporu- 

 lating rods. But to reduce this generalization to definite meas- 

 urements as Lehmann and Neumann have done is not a practical 

 procedure. 



The arrangement of the hacilli in chains is not significant. 

 Probably the aerobes form, chains more frequently than do the 

 anaerobes, but filament formation cannot logically be used as a 

 character for their differentiation. Winslow and Winslow found 

 chain formation a character of minor value in the classification 

 of the streptococci. Certain organisms, e.g., B. Novyi, regularly 

 form filaments on certain media, but the character is of specific, 

 not of generic, value. 



Morphology of colonies would be mercilessly discarded by 

 experimental workers as a means of subdividing a large group 

 like that of the Bacillaceae. It has more value for lower sub- 

 divisions. 



The Gram-stain is an impossible character to use in dividing 

 the Bacillaceae. It fits neither with the morphological char- 

 acters nor with the physiological. There are numerous Gram- 

 positive anaerobes and aerobes, and numerous Gram-negative 

 anaerobes and aerobes. (See Heller, 1920.) 



Granulose (logen) content of the bacterial cells cannot be 

 seriously considered as a general character of anaerobic rods. 



Habitat. Winslow and Winslow found that the Coccaceae 

 could logically be divided according to habitat. The parasitic 

 forms constituted one group and the saprophytic ones another. 

 Certain anaerobes are frequently inhabitants of the intestines 



