abstracts: bacteriology 373 



Mississippi Valley is given. This includes two new formation names. 

 Eau Claire and Mt. Simon (Ulrich MSS., 1914). Numerous faunal lists 

 of these formations and of other Upper Cambrian formations in various 

 parts of the United States which carry Dikelocephalinae are given. 



Several new species are described : three under Dikelocephalus, eight 

 under Saukia, and two under Calvinella. Dikelocephalus lodensis 

 Whitfield has been chosen as the genotype of Saukia; Dikelocephalus 

 osceola Hall, of Osceolia; and Dikelocephalus spiniger Hall, of Calvinella. 

 Another new genus, Hungaia, is also established (p. 351) with Dikelo- 

 cephalus magnificus as the genotype. This genus is not subsequently 

 defined and evidently is not referable to the Dikelocephalinae. 



Edwin Kirk. 



BACTERIOLOGY. — The colon group of bacteria. L. A. Rogers, 

 William M. Clark, and Brooke J. Davis. Journal of Infectious 

 Diseases 4: 411-475. May, 1914. 

 A collection of cultures of the colon type isolated from milk was 

 studied with special reference to the exact determination of the gases 

 formed and the application of these determinations to the classification 

 of the group. It was found that, when determined by exact methods 

 after uniform growth conditions, the volume and relative proportions 

 of the different gases were produced with great uniformity. This char- 

 acter divided the collection into two groups, one of which, characterized 

 by a low volume of gas composed of nearly equal parts of hydrogen and 

 carbon dioxide, corresponds to the B. coli communis and B. coli com- 

 munior type. The remaining cultures produce much greater volume of 

 gas and an increasing proportion of carbon dioxide. The increase in the 

 volume of gas was produced almost entirely by increasmg quantities of 

 carbon dioxide, while the volume of hydrogen remained nearly constant. 

 In many cultures the ratio of carbon dioxide to hydrogen was nearly or 

 quite 2:1. The variations from the type, as well as the variation in 

 duplicate determinations, were much greater in the latter group. The 

 gas ratio was closely correlated with other physiological reactions, espe- 

 cially the fermentation of carbohydrates and alcohols. The fermentative 

 ability was more pronounced in the high-ratio group, but some particular 

 substances were fermented by a large number of the low-ratio group but 

 by only a few of the high-ratio group. Two possible subdivisions, based 

 on fermentative reactions, could be made in the low-ratio group. It was 

 evident that the high-ratio group was made up of a number of types, but 

 sufficient data for their classification were not available. 



L. A. R. 



