130 EXPERIMENT STATION RECORD. [Vol.37 



tions in which the phenomena of oxidation and reduction play a leading or at 

 least an Important part. 



The presence, distribution, and role of arsenic and manganese in plants, 

 F, Jadin and A. Astruc {Rev. Set. IParis], 54 {1916), II, No. 19, pp. 589-593).— 

 Summarizing the more general results of recent and former investigations 

 (E. S. R., 32, p. 628), the authors state that all the organs of all plants an- 

 alyzed by them showed the presence of both arsenic and manganese. The 

 former was present in rather small proportion in a number of plants named, 

 and the latter in larger proportion in a few. The chlorophylliferous portions 

 generally contained more than the subterranean parts, and the content of the 

 leaves varied sensibly with age. 



No preponderant influence is exerted by the soil content of arsenic or man- 

 ganese on the percentage of those substances found in the plants, which take 

 what they require, even, If necessary, through the medium of the plants on 

 which they are parasitic. Vegetable foods constitute, if not the only source, 

 at least one of the most important of the sources of the manganese and arsenic 

 normally found in animal tissues. 



The authors conclude that arsenic and mangane-se are of the greatest im- 

 portance in the vegetable cell, the former exerting an Influence comparable to 

 that of phosphorus, the second favoring the oxygen reactions in the plant. 



Specific action of barium, W. J. V. Ostebhout {Amer. Jour. Bot., S {1916), 

 No. 9, pp. 481, 482). — The author briefly describes experiments with Spirogyra 

 In which the chloroplasts were characteristically contracted toward the centCr 

 of the cells when the filaments were subjected to 0.0001 molecular solution of 

 barium chlorid. This action is considered specific for barium, no other salt 

 examined producing this effect at such dilutions. 



The plant as an index of smoke pollution, C. Ckowtheb and A. G. Rtjston 

 {Abs. in Rpt. Brit. Assoc. Adv. Sri., 85 {1915), p. 780). — The re.sults are re- 

 ported of experiments and observations during several years on the types of 

 vegetation Injured by smoke, the general appearance of plants so injured, and 

 the specific effects of smoke on plants. 



The authors state that where smoke Is excessive trees and shrubs make only a 

 stunted growth. Bulbous and seed-bearing plants are sensitive to smoke, coni- 

 fers particularly so. Hawthorn barely persists in such areas, leguminous planta 

 rapidly disappear, and coarse grasses and weeds monopolize meadows and 

 lawns, while rhubarb Is very little or not at all affected, and elder prows suc- 

 cessfully in such regions. 



Destruction of buds and young shoots is noticeable. Characteristic discolora- 

 tion of leaves occurs and the leaves fall earlier than normally. Colors are 

 weakened, blues and reds tending to white and bronzes to pale yellow, and 

 certain deflnlteness of correlation appears between depth of tinting and 

 smoke pollution. The choking of stomata by soot particles has been observed 

 to occur. Crop yields are lowered by excess of smoke, and development of root 

 structures is found to be retarded. A relatively high content of chlorin. of 

 arsenic, and especially of sulphur In nonprotein forms In plants is observable. 



Seeds in smoke-polluted areas show decrease as regards size, weight, ger- 

 mination capacity, and germination energy. Inhibitory effects upon enzym 

 activity have been deraonstratetl by comparative measurements of the activity 

 of oxidase, catalase, lipase, and emulsin. 



Teratology in iris flowers, Ei.e.\nora Armitage {Gard. Chron., S. scr.. 60 

 {1916), No. 1557, p. 203). — Abnormalities relating to the number, shape, arrange- 

 ment or fusion of floral parts are noted as occurring In different species and 

 varieties of iris. 



