AGBICULTURAL BOTANY. 627 



true." A calcium oxld content of less than 1 per cent is considered relatively 

 low, and corn, oats, rye, wheat, and millet belong to this class. A content of 

 more than 1 per cent is consiilered high, and to this class belong peas, clover, 

 alfalfa, buckwheat, and most of the species of Cruciferjp. The author considers 

 that the feeding power of a plant for an insoluble substance depends primarily 

 upon two conditions, (1) the solubility of that substance in carbonated water, 

 antl (2) whether or not the plant removes from solution all tlie products of the 

 solubility reaction in the proper proportion, so as to allow the solubility reaction 

 to continue indefinitely. 



The presence of inorganic iron compounds in the chloroplasts of the green 

 cells of plants, considered in relationship to natural photosynthesis and the 

 origin of life, B. Moore (Proc. Roy. Soc. [Loudon^, Ser. B, 87 (1914), No. 

 B 59S, pp. 556-570). — The ar.thor discusses experimentation designed to throw 

 light upon the processes taking place and the substances occurring in the wide 

 hiatus between the simple colloidal molecules of inorganic iron salts gr oxids 

 in the solution or suspension, which, as shown by Moore and Webster (E. S. R., 

 30, p. 129), possess the power of synthesizing formaldehyde in the presence 

 of carbon dioxid with sunlight as energ>' supply, on the one hand, and such a 

 highly, complex organic substance as chlorophyll, on the other. It is stated that 

 Inorganic iron salts and iron or aluminum hydrates in colloidal solution possess 

 the power of transforming the energj' of the sunlight into the chemical energy 

 of organic compounds. Inorganic iron in crystalloidal or colloidal form is 

 thought to be present in the colorless part of the chloroplast of the green plant 

 cell in many plants. In the absence of iron the green coloring matter can not de- 

 velop in the leaf, although the green coloring matter itself contains no iron. 

 In the presence of sunshine the iron-containing substance of the chloroplast de- 

 velops the coloring matter, so that this itself is a product of photosynthesis 

 induced by the iron-containing compound. 



It is held that these facts afford an explanation of chlorosis and of its cure 

 by inorganic iron salts, and demonstrate that iron is a primary essential in 

 photosynthesis and the production of chlorophyll. The iron-containing sub- 

 stances of the colorless portion of the chloroplast and the clilorophyll produced 

 by tliem thus become associated in the functions of photosynthesis as a com- 

 plete mechanism for energy transformation. 



Nitrites in plants, K. Aso and T. Serine (Bot. CentN., Beihefte, 32 (1914), 

 1. AM., No. 1, pp. 146, 147). — The authors, noting the statement of Klein 

 (E. S. R., 30, p. 30) regarding the absence of nitrites in underground portions 

 of Sayittaria sagittifolia, report a study of cases in which nitrites were doubt- 

 less present, though in slight concentrations, in the shoot-like buds of this plant. 

 The nitrites were supposedly produced either by physiological oxidation of 

 amido acids or by reduction from nitrates. 



Free nitrogen and higher plants, M. Molliard (Compt. Rend. Acad. Sot. 

 [Paris], 160 {1915), No. 9, pp. 310-313).— Repovtiug and discussing his own 

 experimentation testing for an alleged capability of higher plants to utilize 

 atmospheric nitrogen, as upheld by Mameli and PoUacci (E. S. R., 25, p. 633; 31, 

 p. 223), the author concludes that Raphanus sativus does not utilize the free 

 nitrogen of the air. 



Studies on anthocyanin bodies, O. Gertz {Svensk. Bot. Tidslcr., S (1914), 

 No. 4< PP- 405-435, figs. 20). — The author gives an account of his observations 

 on the various forms, structures, locations, arrangements, etc., of anthocyanin 

 bodies as studied in more than 40 plant species belonging to almost as many 

 genera, with a discussion thereof and of some related literature, which is listed 

 in this connection. 



