AEROBIC SPORE-BEARING NON-PATHOGENIC BACTERIA 527 



CLASSIFICATION 



BY W. W. FORD 



From a study of spore-bearing organisms lasting over a period 

 of four years, during which over 1700 cultures were worked out 

 from a variety of sources including milk, dust, water, soil, in- 

 testinal contents, and laboratory stock cultures 28 species or 

 varieties of species were isolated and established as distinct 

 types by the usual moi-phological, developmental, tinctorial and 

 cultural features available for systematic investigation. The ma- 

 jority of these types were encountered on many separate occa- 

 sions and our descriptions of them are based upon those fixed and 

 permanent characters which we regard as establishing bacterial 

 species. These types thus represent the organisms met with in 

 our work quite regardless of their identification as previously 

 established species or varieties. Of the total number, 28, we 

 were able to identify 22 as species already described in the lit- 

 erature. Whether these species are correctly named, is a mat- 

 ter about which of course opinions may vary. We feel however 

 that our identification of these 22 species is as satisfactory as 

 the confusion in the literature and the uncertainty of stock cul- 

 tures permit. In addition to the 22 types described by previous 

 workers two distinct varieties of old species were found while 

 four organisms were isolated which are so different from any de- 

 scribed in the hterature as to merit estabhshment as new species. 

 To these six organisms new names have been given. With these 

 28 types in mind it now becomes possible to classify the spore- 

 bearing organisms from a preliminary standpoint. The basis 

 for the classification rests primarily upon morphology, spore- 

 formation and motility, and secondarily upon tinctorial and cul- 

 tural features. All the characters are easily demonstrated m any 

 properly equipped bacteriological laboratory. Both the mi- 

 crochemical properties of the bacterial cells and the methods of 

 spore-germination while studied when possible have been dis- 

 regarded in arranging the species in groups. The extent to 

 which this classification is of permanent value will be shown, we 

 believe, by the approval or disapproval with which it is received 

 by American bacteriologists. 



