AGRICULTURAL BOTANY. 131 



p. 616). — The author gives the results of his investigations on plants regarding 

 the differences observable in chemical composition, etc., between plants ex- 

 posed to an atmosphere of narcotics and those in air. These in the main may 

 be summed up as follows: Plants in a narcotic atmosphere show (1) increase 

 of soluble, osmotically active compounds, as sugar, asparagin, etc.; (2) height- 

 ened turgor; (3) cells growing in a form shorter but thicker with other cell 

 modifications, as increase of collenchyma, epidermal thickenings, vacuolization 

 and fusion of cells, etc.; (4) lessened synthesis of proteins and coloring mat- 

 ters; (5) alterations of negative geotropism; and (6) increase of heliotropic 

 sensitiveness. 



The stimulation of plants through small quantities of poisonous sub- 

 stances, E. B. Fred {CentU. Bald, [etc.], 2. Abt., 31 (1911), No. 5-10, pp. 

 185-2/i5, figs. J,; ads. in Jour. Chem. Soc. [London], 100 {1911), No. 590, II, 

 p. 1123). — A detailed account is given of experiments in which ether, carbon 

 bisulphid, potassium bichromate, copper sulphate, and Salvarsan were tested 

 on various organisms. It was found that their effect is a biological one and 

 that when used in sufficient dilutions they promote the growth of Azotobacter 

 and of denitrifying, ammonifying, and various putrefactive bacteria and yeasts. 



Ether in a suitable quantity increased the nitrogen fixation by Azotobacter in 

 soils, and both ether and carbon bisulphid increased nitrogen fixation in pure 

 cultures, but not so much as in mixed cultures talren directly from soil. This 

 is probably due to Azotobacter's possessing a greater resistance to the chemical 

 materials used than the other organisms; the energy which the second class of 

 organisms would use thus goes to aid in the development of the more resistant 

 forms. The growth of denitrifying bacteria was retarded through the presence 

 of the antiseptics, although there was ultimately a small increase in total 

 production. Denitrification, it is claimed, plays no important role in normal 

 soil where there is no pronounced source of carbon present. 



In ordinary soils nitrification was for a time retarded by the application of 

 ether, but later it was considerably increased. The stimulating effect of ether 

 and carbon bisulphid on the growth of plants in sterile soil was demonstrated. 



In conclusion the author states that the beneficial effect of the substances 

 tested is due to their stimulating action on the plants themselves as well as the 

 effect they exert on the lower organisms. 



An extensive bibliography is appended. 



Action of carbon bisulphid on germinability of grain, A. Morettini (Staz. 

 Spcr. A(ir. Itah, U {Wll), No. 5-6, pp. f, 17-', 22). —The author conducted a 

 series of experiments to determine the injury to germinability of grain caused 

 by the application of carbon bisulphid vapor for the purpose of combating in- 

 jurious insects. Two lots of grain were employed, the germinability of which 

 was from 99 to 100 per cent before treatment. 



In a series of exposures to the vapor lasting from 1 to 60 days the germination 

 decreased from 92 to 0.5 per cent for one kind of grain, and from 89 to 15 per 

 cent for the second. Smaller quantities of the gas caused less injury. The 

 smallest quantity that was effective as an insecticide was about 31.55 gm. of 

 the poison per hectoliter of grain. This could be continued for 16 days without 

 reducing the germinability below 98 per cent, and after 100 days it was not 

 below 95 per cent. About 35.9 gm. per hectoliter is considered a safe proportion 

 to employ for a period necessary to protect the grain. 



The action of carbon bisulphid on the germination of wheat, P. Fantechi 

 (Staz. Spei: Agr. Ital., J/J, {1911), No. 7, pp. 515, 5i 6). —Attention is called to 

 experiments made by the author in 1900 upon the effect of carbon bisulphid 

 on the germinability of wheat. He claims to have found that the vapor of car- 

 bon bisulphid as commonly used to destroy insects in stored grain did not 



