AGEICULTUEAL BOTANY. 431 



The fixation of nitrogen by free living soil bacteria, W. B. Bottomley 

 (Proc. Roy. Soc. [London], Ser. B, 82 {1910), No. B560, pip. 627-629; Ghem. 

 News, 102 (1910), No. 2652, p. 155; ahs. in Jour. Soc. Chem. Indus., 29 (1910), 

 No. 19, p. 1171). — Culture experiments with Azotobacter and Pseudomonas 

 showed that these organisms fixed more nitrogen when grown together than 

 when grown separately, and that the mixed culture was more active ou limed 

 soil than on unlimed soil. Experiments with different soils showed an increase 

 in nitrogen following inoculation with the mixed culture in all cases. 



The amid nutrition of green plants, J. Lefevke (Assoc. Franc. Avanc. 8ci.. 

 Compt. Rend., 37 (1908), pp. 5Ii2~5.ii-'i). — As the result of a series of experiments 

 under sterile conditions, the author confirms his previous conclusions (E. S. R., 

 18, p. 26) that green plants can assimilate amids in the absence of carbon 

 dioxid. 



His experiments here reported were conducted with maize and pine seed- 

 lings, and in the case of the former the plants showed considerable increase 

 in their dry weight when grown in Knop's solution containing 0.5 per cent 

 amid. No increase in dry weight occurred in the absence of the amid. It was fur- 

 ther found that while growing plants can utilize amids. embryos can not do so. 



The production of hydrocyanic acid in Arum maculatum, A. Hebert and 

 F. Heim (Assoc. Franc:. Avanc. ScL, Compt. Rend.., 37 (1908). pp. 352, 353). — 

 Accoi'ding to the authors, hydrocyanic acid exists in a free state in A. macula- 

 turn only in the gi-een parts of the plant and is not formed in any portion 

 where chlorophyll is lacking. In the leaves the proportion of hydrocyanic 

 acid increases from the time they appear above ground until the oi^ening of 

 the spathe, after which there is a progressive loss. It is absent in the flower 

 parts in all stages of their development, and the authors claim that there is 

 no warrant for the hypothesis of Blisch that it has a toxic effect on insects 

 visiting the flowers, as there is not a trace to be found. The small amount 

 present in the plant the authors believe, can not be considered as a defense 

 against leaf-eating animals. 



The oil of bitter almonds in Centaurea aspera, C. Gerber and J. Cotte 

 (Assoc. Franc. Avanc. Sci., Compt. Rend., 37 (1908), pp. 522, 523). — The authors 

 report the presence of oil of bitter almond, benzaldehyde, in the distillate ob- 

 tained from macerated gi'een leaves of C. aspera, and accompanying it was 

 found hydrocyanic acid. These bodies, the authors claim, do not occur free in 

 the plant but in a glucosid of the amygdalin group. The function of hydro- 

 cyanic acid is held to be not protective but a stage in the albuminoid synthesis 

 of the plant. 



Photochemical synthesis of carbohydrates in the absence of chlorophyll, 

 J. Stoklasa and W. Zdobnicky (Chem. Ztg., 3.'f (1910), No. 107, pp. 9-'i5, 

 946). — The authors have investigated the possibility of the synthesis of carbo- 

 hydrates in the absence of chlorophyll by exposing carbon dioxid and nascent 

 hydrogen to the influence of ultraviolet rays. Photosynthesis was effected, the 

 reaction being according to the following formula : 2C02+2H2=2HCOH+02. 

 The formaldehyde in this was condensed by potassium hydroxid into sugar. 

 Formaldehyde was not formed in the absence of the ultraviolet rays, and while 

 it was produced in small quantities from carbon dioxid and vapor, it was im- 

 possible to condense it into sugar. 



The action of ultraviolet rays in the presence or absence of chlorophyll in 

 the higher plants, as well as on the formation of carbohydrates, is a subject 

 under investigation. It has already been found that photosynthesis in etiolated 

 plants is greatly stimulated by the action of these rays. 



The utilization of xylan by Xylaria hypoxylon, M. Molliard and C. L. 

 Gatin (Bui. Soc. Bot. France, 57 (1910), No. 2, pp. 127-131).— As a result of 



