EVOLUTION AND CLASSIFICATION OF BACTERIA 457 



CONCLUSIONS 



In spite of all these criticisms of the report in matters of detail, 

 it should be recognized that the committee has drawn up an 

 admirable summary of the present status of systematic bacteri- 

 ology. In matters of opinion, the names of the six members of 

 the committee carry a great deal of weight. Even in matters 

 of detail their classification is as satisfactory as could be drawn 

 up by any other similar group of men. The report is, in reality, 

 open to criticism mainly because of the extent of the undertaking 

 which the society has placed upon the committee. No other 

 committee on systematic biology appointed by a national or 

 international society has ever undertaken such an ambitious 

 task as a complete classification of any group of animals or plants. 

 Other committees of this sort have done nothing further than 

 to pass upon the validity of generic and specific names submit- 

 ted to them, leaving it to individual initiative to propose new 

 names, to classify and to define the groups. 



Summing up the suggestions made above, the following classi- 

 fication of orders and families of Schizomycetes is obtained: 



Order I. Euhacieriales. Cells minute; spherical, rod-shaped, 

 or spiral, often occurring in chains, -but never in branched or 

 sheathed filaments. 



Family 1. Pseudomonadaceae. Cells generally rod-shaped, 

 though occasionally spherical. If motile, flagella occur at the 

 pole. No endospores. Generally Gram-negative. Primarily 

 water and soil forms. Sometimes able to assimilate inorganic 

 nitrogen and to obtain energy from the oxidation of inorganic 

 compounds. Often parasitic to plants, seldom to animals. 



Family 2. Spirillaceae. Cells more or less spirally curved. 

 If motile, flagella are polar. 



Family 3. Coccaceae. Cells in their free conditions spherical; 

 during division somewhat eliptical. Motility rare. Endospores 

 absent. Often parasitic on animals. 



Family 4- Bacteriaceae. Rod-shaped cells without endospores. 

 Generally Gram-negative. Flagella when present peritrichic. 

 Saprophytes, animal parasites and plant parasites. 



