AGRICULTURAL BOTANY. 831 



It appears ovident thai the forniatioii of insohibU' and coasulahle protcids 

 is more active in suiilij;lit than in darkness, eansin^' a decrease (if albmnoses 

 Iteptones. and diannno compounds. 



On the variation in the dry weight of plants under different light intensi- 

 ties, W. LuniMENKo (Coiniit. Rend. Acad. Sci. [Paris], 1J,5 (1907), No. 2Jf, pp. 

 1191-1 i<l4, (Igtn. i).— In a previous publication (E. S. R., 19, p. 22), the author 

 has shown that the optimum illumination for the assimilation of organic mate- 

 i-i:ils by liernnnatin.i,' plants is somewhat below that of the optimum for photo- 

 synthesis. These studies suggested an examination of the relation between 

 illumination and increase in dry weight of green plants. By means of specially 

 constructed frames, the author carried on experiments with 12 species of plants, 

 analyzing samples every 10, 1.5, 20, and 30 days to determine their fresh and 

 dry weight. 



In 34 experiments, in all but 7 cases the maximum dry weight was secured 

 where the light intensity was less than that of full summer sunlight. In prac- 

 tically every case there was a gradual increase in dry weight up to a certain 

 degree of illumination, after which a marked falling off was noted. 



The injurious effect of prolonged exposure to very strong light is attributed 

 to the retarding effect the light has upon certain organic materials which 

 result from the decomposition of carbon dioxid by chlorophyll. 



The action of a magnetic field of high frequency on Penicillium, P. Lesage 

 (Conipt. Rend. Arad. i-ici. [Paris], lJ,o (1901), No. 25, pp. 1299, 1,300).— A study 

 was made of the germination of spores and the growth of mycelium of Penicil- 

 lium in a magnetic field of high frequency. It is claimed that germination 

 and growth were accelerated, but that the action was probably indirect and 

 due. in iiart at least, to the heating of the solenoid. 



Influence of stimulating compounds upon the crops under different condi- 

 tions, S. UcHiYAMA {Bui. Imp. Cent. Agr. Expt. 8ta. Japan, 1 (1901), No. 2, pp. 

 37-79, pis. J/). — Plat and pot experiments in which the stimulating effect of man- 

 ganese sulphate at rates of from 10 to nearly 40 kg. per hectare, as well as of 

 iron sulphate, iodin, and fluorin on a great variety of crops under varying condi- 

 tions of acidity and alkalinity of the associated fertilizers and in the character 

 of the soil was studied, are reported. 



The results show that both the manganese and the ii'on comitonnds stimulated 

 the growth of croi)s, the action of the salts varying considerably with the char- 

 acter of the plant. In some cases joint application of the manganese and iron 

 salts gave better results than either salt alone. In other cases the opposite 

 result was obs.^rved. As a rule the manganese sulphate gave better results than 

 the iron sulphate, but its action varied greatly with the character of the soil, 

 the method of ai)plication, and the nature of the associated fertilizing materials. 

 The best results were obtained when the manganese sulphate was applied as 

 a top-dressing and in fertilizer mixtures which had a nearly neutral reac- 

 tion. Applications of from 20 to HO kg. of crystallized manganese sulphate per 

 hectare (is to 4~> li)S. per acre) are considered sutlicienl. 



The stimulating effect of potassium iodid and sodium lluorid varied widely 

 with different plants. From 2.5 to .500 gm. of potassium iodid and 100 to 1,000 

 gm. of sodium tluorid per hectare are considered suitable applications of these 

 materials. 



The toxicity of the salts of chromium, aluminium, and magnesium ixi com- 

 parison with similar properties of some rare metals, A. IIkhkut (HiiI. Soc. 

 Vliini. France, ',. srr., I (1907), No. 1^-19, pp. 1020-10,12) .—A study was made 

 with the sulphates of chronnnm. aluminium, and magnesium to determine their 

 relative t<jxicity, and conii>arisons were made with similar salts of some of the 

 rarer metals, as zirconium, thorium, cerium, lanthanum, etc. The effects of 



