PROSPECTS FOR A NATURAL SYSTEM OF CLASSIFICATION OF BACTERIA 



On the other hand it seems to us that the system as outlined in this 

 paper marks a definite progress as compared with previous ones. To 

 justify this statement it will suffice to bring out two features. 



Firstly the system given is characterized by its simplicity as well as 

 by its consistency. The principle that a genus in all cases is defined 

 by the fundamental morphological and katabolic properties makes 

 for units which are much more easily distinguishable than the majority 

 of the genera in the previous systems. In addition the system offers the 

 advantage of permitting the ready incorporation of organisms with 

 still unknown combinations of morphological and physiological char- 

 acters. Therefore it may lay claim to the epithet 'rational'. 



But secondly it seems to us that to a certain extent the system, al- 

 though artificial, also answers the requirements of a true natural 

 system. For the natural relationships between the various bacteria 

 which in the present state of our knowledge can be vaguely perceived 

 find a definite expression in the aspect of the system. That this aspect 

 is not final is certain. Future investigations will deepen our insight into 

 the natural relationships of different bacterial groups and the system 

 will have to be modified accordingly. 



Nevertheless it appears likely that the idea which is largely respon- 

 sible for the outline, viz., the occurrence of both morphological and 

 katabolic evolution in the bacterial kingdom, will reappear in future 

 classifications, thus perhaps justifying the use of the word prospects 

 in the title of this paper. In the meantime the system in its present 

 imperfect shape may well serve the purpose of stimulating interest and 

 research in this field. 



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