536 HILDA HEMPL HELLER 



Nitrogen-fixing anaerobes that split carbohydrates. E.g. Clos- 

 tridium Pastorianum Winogradsky, a large anaerobic rod that 

 forms oval spores. 



Carbohydrate-splitting anaerobes that can utilize fixed nitrogen 

 but not free nitrogen. They do not produce gross proteolysis. 

 E.g. vibrion septique. 



Anaerobes that split proteins very actively. Some but not all 

 have lost the power of splitting carbohydrates. E.g. the sporo- 

 genes type. 



Geologically this sequence would be the most natural. But 

 we know so little about bacteria and their evolution that any- 

 evolutionary arrangement is little more than guess-work at the 

 present time. 



It is my intention to propose a division which seems more 

 logical than "the Bacillaceae, spore-bearing rods," as dis- 

 tinguished from the "Baderiaceae, non-sporulating rods of higher 

 metabolism." This division implies the creation of a family: 

 "The Clostridiaceae, rod-like forms, not spiral, which will not 

 grow within seven millimeters of the surface of a shaft of clear 

 tissue-free agar medium contained in a tube 12 millimeters or 

 more in diam-eter, incubated in air, in which they are able 

 to grow in the depths. They may or may not possess peritrichial 

 flagella; they may or may not form spores. Most members of 

 the group are characterized by their energetic action on proteins 

 or on carbohydrates or on both of these types of substances." 

 It would be unwise to claim that we have evidence to show that 

 these organisms are descended from a single type — in other 

 words that this is a perfectly logical classification. Bacteriol- 

 ogists have no characters available for purposes of classification 

 whose nature is sufficiently understood to grant us the liberty 

 to make such assumptions. But I believe that this primary 

 division will separate fewer types that are physiologically alike 

 than any other thus far proposed. The energetic action of the 

 anaerobic non-fusiform rods upon carbohydrates and proteins 

 is characteristic and separates them from most other groups. 

 In the present state of our knowledge it is only the separation 

 of types that have several characters in common that is care- 



