96 FRED W. TANNER 



the 100 strains fall into 9 groups all of which are very closely 

 related. 



The group number probably does not separate bacteria along 

 natural lines, but it does constitute a convenient method for 

 considering the characters of such closely related bacteria as 

 make up the fluorescent group. It obviates the necessity for 

 bacterial names which have very little meaning in present bac- 

 terial work. Especially true is this in regard to the fluorescent 

 group. The group number places equal emphasis on ail the 

 determinations which it expresses. It is quite probable, too, 

 that many of the inadequacies of the group number may be 

 explained by the lack of proper methods for determining the 

 characters for which it calls. 



Four of the cultures form endospores, which have been ac- 

 cepted by bacteriologists as a reliable and important basis for 

 separating bacteria. De Bary placed so much importance on 

 this that he described minutely the formation and germination 

 of spores. This characteristic is one of importance which indi- 

 cates that the fluorescent bacteria may not be a genetic group. 

 Edson and Carpenter, however, report no spore-forming fluo- 

 rescent bacteria in their study of maple sap. 



The presence of a proteolytic enzyme for gelatin might be of 

 more value in classification were a satisfactory method available 

 for detemining its presence. With the fluorescent bacteria this 

 has been taken as the sole difference between certain members of 

 the group. The 100 strains forming the basis of this study were 

 about evenly divided with respect to this characteristic. 



Gelatin liquefaction paralleled casein digestion closely, al- 

 though sixteen strains which liquefied gelatin failed to split 

 casein. Of the cultures which liquefied gelatin, the majority 

 liquefied between 40 and 50 mm. The others graded away from 

 this group and one may infer that the determination, as it is 

 now made, is not sufficiently delicate for classification purposes. 

 Those strains which required four or five months for liquefaction 

 to appear might be regarded as the links between the liquefiers 

 and the non-liquefiers, or they might represent transitional forms 

 which are in the act of acquiring or losing this characteristic. 



