1911] CURRENT LITERATURE 489 
a hexose phosphate containing two phosphoric acid residues. The evidence 
is based largely on the composition of the barium salt of the compound, an 
on the behavior of its ozazones. In the formation of the ozazone, a single 
phosphoric acid molecule is split off, while the ozazone also contains a phos- 
phoric acid residue. 
It has been known that yeasts are able to ferment a number of substances 
other than sugars. The number of such substances which undergo a kind of 
fermentation accompanied by the evolution of carbon dioxide has been greatly 
extended by NEUBERG and Tir.* The substances which are fermented in this 
way by yeasts and yeast preparations are the common plant acids which occur 
naturally in fruit juices and other substances used in alcohol production, and 
also components or products of the yeast cell, as fatty acids, glycerine, and 
lecithin —H. HassELBRING. 
Soil productiveness indicated by natural vegetation.—The practical 
object of SHANTz’s Bulletin? on “Natural vegetation as an indicator of the 
capabilities of land for crop production in the Great Plains area”’ does not 
detract from its scientific value. It is an interesting and valuable example of 
the application of exact ecological research methods, with results establishing 
reliable data relating to the natural vegetation of a given region, and its corre- 
lation with the crop-producing capabilities of the land. Detailed investiga- 
tions were made in Washington and Yuma Counties, Eastern Colorado, al- 
though a general survey included all the states of the Great Plains, a region 
containing the largest body of land of possible agricultural importance in the 
United States on which the native plant cover still exists. The methods 
included study of the vegetation with respect to the formations, dominant 
associations, and important species, and of the various determining factors with 
especial consideration of the physical conditions (temperature, rainfall, evapora - 
tion, saturation deficit, soil moisture, soil temperature, etc.). Records for 
these physical factors were made at 11 different stations on the Great Plains, 
under direction of Briccs, and supplemented by SHANTz with many compara- 
tive observations. For purposes of comparison, the soil moisture determina- 
tions were reduced to definite standards, as moisture equivalent and non- 
available moisture (for Kubanka wheat). 
Plant migrations, invasions, effects of fire, grazing, mowing, and other 
biotic agencies are considered. Illustrations of the root systems of significant 
species are given and their relations to the soils and in the successions are noted. 
Indicative of agricultural land are the grama-buffalo grass and the wire grass 
28 NEUBERG, C., and Tir, L., Ueber zuckerfreie Hefegdrungen. II. Biochem. 
Zeitschr. 32:323-331. IQII. 
- 99 Santz, H. L., Natural vegetation as an indicator of the capabilities of land for 
crop production in the Great Plains area. Bur. Pl. Ind. Bull. no. 201. pp. 100. 
S. 6. figs. 23. IQII. 
