456 E. S. BREED, H. J. CONN AND J. C. BAKER 



most conservative procedure is to leave these forms in the Bac- 

 teriaceae. 



Family 8. Bacillaceae. This family, for the spore-forming 

 rods, has very good justification. The two genera, Bacillus 

 and Clostridium, can probably be separated, but whether on the 

 basis of relation to oxygen or of shape of the sporangium, the 

 future must decide. Although relation to oxygen is a very 

 important physiological distinction, it must be admitted that 

 the selection of a physiological basis for the separation of these 

 two genera is rather unsatisfactory. It places some of the polar- 

 spored organisms in one genus, some in the other, and raises the 

 question where to place facultative anaerobes like B. mycoides 

 and B. cereus. 



Type species. At the 1916 meeting of the society, the com- 

 mittee on classification proposed that American bacteriologists 

 follow the international code of nomenclature adopted at the 

 Vienna Botanical Congress. No opportunity had been given 

 the society to study into the matter, and naturally the resolu- 

 tion was passed. It seems, however that the Vienna code does 

 not recognize the principle of type species. The committee on 

 classification (p. 531, footnote) states that the principle of type 

 species "affects bacterial taxonomy less than other divisions of 

 taxonomy." In this opinion they are decidedly open to criticism ; 

 for the very difficulty in defining bacterial genera and species 

 accurately makes it imperative that no genus be recognized 

 without a well-defined type. The fact that the society took 

 action in favor of the Vienna code does not absolve bacteriol- 

 ogists from accepting this fundamental principle of nomencla- 

 ture as it is recognized by zoologists and by many botanists. 



The committee has plainly considered tj^pe species unnecessary, 

 for they have omitted to mention them for the following genera: 

 Nocardia, Pseudomonas, Spirillum, Albococcus, Rhodococcus, and 

 Erwinia. Some of these genera may easily be assigned type 

 species (e.g., Albococcus pyogenes (Rosenbach) Winslow); but 

 for others, such as Nocardia, none is available. It is especially 

 unfortunate that the committee has neglected to name a type 

 .species for Erwinia, which they describe as a new genus. 



