526 EXPERIMENT STATIOlSr RECORD. (Vol.43 



Tlie authors state in the general conclusion to this work that the yellow pig- 

 ment was not found to function either in assimilation or in respiration. Chloro- 

 phyll, on the contrary, unites with its ordinary and apparent function, another 

 which is more dithcult to detect and which is related to its capahility to react 

 chemically. This pigment is decomposed in connection with a reaction of carhon 

 dioxid in the presence of magnesium, an intermediate product heing a dis- 

 sociable carhon dioxid compound. A theory of assimilation is outlined with 

 supporting conclusions. 



Willstatter and Stoll's recent work on assimilation by plant.s, H. Borut- 

 TAu {Umschau, 22 (1918), No. 9, pp. 100-102). — This is a review of some fea- 

 tures (largely chemical) of recent work by Willstiitter and Stoll, as embodied 

 in the volume above noted. 



The water absorption region of roots, H. CorpiN (Cotnpt. Rend. Acad. Sci. 

 [Paris], 168 {1919). No. 20, pp. 100.5-1008).— Vuvsuing studies as previously in- 

 dicated (E. S. R., 42, p. 819), the author found that no advantage was gained 

 by immersion of more than the tip of a root in water. He claims that water 

 In the plants tested is absorbed exclusively by the root tip, the root hairs not 

 functioning in this regard. 



The response of plants to wireless stimulation, J. C. Bose {Nature [Lon- 

 d07i], lOJ, {1919), No. 2609, pp. 172-17-',. flgs. 2).— The author states that investi- 

 gations regarding the influence on plants of ultra-violet and infra-red spectral 

 wave lengths have shown that the very short electric waves retard growtli, pro- 

 ducing responsive movements in Mimosa when in a highly sensitive condition. 

 A definite mechanical and electric response to wireless impulse was obtained 

 with all plants tested. The arrangement employed is briefly described as to the 

 production and effect both of strong and of weak stimuli. It is claimed that 

 the perceptive range of plants is very great, and that they not only perceive but 

 i-espond to the different wave lengths of the vast ethereal spectrum. 



The influence of colored lights on the coloration of Cyanophyceje, K. 

 BoBEscH {Ber. Dcut. Dot. Gc^cll., 37 {1919), No. 1, pp. 2o-.3fl).— The capability 

 of certain Cyanophyceae to modify the color of incident light by assuming a com- 

 plementary color was demonstrated for Plwrmidium fovcolaniin. This is dis- 

 cussed in regard to its probable significance. 



The fate of chlorophyll in plants in autumn, R. Kolkwitz {Bcr. Dcut. Bot. 

 GeselL, 37 {1919), No. 1, pp. 2-5). — Observations are noted as made on changes 

 affecting chlorophyll in plants, covering a wide range as regards systematic 

 arrangement. 



FIELD CROPS. 



Practical universality of field heterogeneity as a factor influencing plat 

 yields, J. A. Harris {.Jour. Agr. Research [[/. -S.], 19 {1920), No. 7, pp. 279- 

 314). — This paper presents the results of studies with reference to the use of 

 the modern higher statistical methods in the analysis of data from plat tests in 

 field experiments. The particular phase of the problem dealt with is the lack 

 of uniformity of the experimental field. Data secured by other investigators are 

 reviewed, a bibliography of 22 references to the literature cited is given, and 

 the results of the author's own studies are presented in tables and discussed. 



Heterogeneity is defined as differences in capacity for crop production 

 throughout the field of such a magnitude as to influence in like manner, but not 

 necessarily to like degree, the yield of adjacent small plats, and it is pointed 

 out that this factor is measured by a coefficient which shows the degree of cor- 

 relations between the yields of associated ultimate plats, grouped in combina- 

 tion plats. The determination of this coefficient for a relatively large series 

 of experimental fields, widely distributed throughout the world and planted to a 



