AGRICULTURAL BOTANY. 225 



firming previous conclusions reached by the author in connection with Ancelin 

 (E. S. R., 29, p. 32G). 



The determination of the rays concerned in chloropliyll synthesis, P. A. 

 Dangeard (Botaniste, 12. ser., 1912, pp. XXI-XXVI; ahs. in Ann. Bot. [Rome^, 

 11 {1913), No. 3, pp. 501, 502).— The author investigated further (E. S. R., 25, 

 p. 221) the influence on chlorophyll synthesis of the different portions of the 

 spectrum obtained from a Nernst lamp, employing in these later experiments a 

 quartz prism. 



It is stated that there exists a direct relation between the growth of a green 

 alga and the absorption of radiations by its contained chlorophyll, the maximum 

 effect appearing between the lines of wave length 6G0 to 670. The rate of 

 absorpton of chlorophyll in solutions by an alga or its rate of vegetative develop- 

 ment therein corresponds closely to the concentration employed. Notwithstand- 

 ing considerable absorption of xanthophyll below line 490, the energy absorbed 

 is insufficient to cause chlorophyll sj'uthesis in that part of the spectrum. It is 

 also claimed that blue and violet rays do not appear to have any important 

 influence on chlorophyll synthesis. 



New observations on chlorophyll assimilation and reply to recent criti- 

 cisms, P. A. Dangeakd (Bui. Soc. Bot. France, 60 {1913), No. 2-3, pp. 166- 

 175). — Referring to results obtained from work above noted and calling atten- 

 tion to observations of other investigators, the author replies to certain objec- 

 tions offered to his previous conclusions. 



Two years' experiments with static electricity as related to the growth of 

 cultivated plants, P, Trnka {ZcmedelsJcij Arch. {Arch. Bodcnkult. Bohnien), 

 Jf {1913), No. 1; al)S. in Bot. CentU., 123 {1913), No. 6, p. 138).— The author 

 gives an account of experiments in which insulated wire nets stretched at a 

 height of 4 or 5 meters above 36 hectares of growing beets were subjected to 

 an electric current of from 50,000 to 70,000 volts and 0.7 to 0.8 milliamperes for 

 1,468 hours in 223 days of 1911, and 2,000 hours in 299 days of 1912. 



The production of the field was sensibly increased, but the question as to the 

 profitableness of the treatment was not fully settled. Differences in chemical 

 composition were noted, both during the growing period and after maturity. 

 These increased yields appear not to be explainable as due to differences in 

 transpiration, stimulation, or assimilation processes, and this fact leads to the 

 supposition that the electricity exerts its direct influence upon the soil rather 

 than upon the plant. This mode of culture is thought to be better suited to 

 plants having large assimilation surfaces. 



On the growth of plants in partially sterilized soils, E. J. Russell and 

 F. R. Petherbridge {Jour. Agr. Sci. [England], 5 {1913), No. 3, pp. 248-2S7, 

 pis. 4, fig. 1). — For a number of years experiments have been in progress in 

 growing plants in partially sterilized soils, and some of the observed facts are 

 placed on record. The partial sterilization was effected by the use of toluene 

 and by heating to 55 and 100° C. 



The germination of seeds planted in these soils was sometimes hastened, at 

 other times retarded. Retardation was almost always produced in soils heated 

 to 100° or treated with toluene, while acceleration often followed the planting 

 of seeds in soils heated to 55°. The retarding effect was generally more pro- 

 nounced in moist than in dry soils and in rich than in poor ones. 



In the seedling stages the plants produced on partially sterilized soils were 

 sometimes indistinguishable from those on untreated soils. Seedling tomatoes 

 grown on heated soils in comparison with those grown on untreated ones had 

 smaller roots and smaller cotyledons of a darker green color, frequently show- 

 ing some purple. The effect on the seedlings was most pronounced during the 

 dull days of winter, and this has a practical application in the use of partial 



