124 EXPEEIMENT STATION EECOKD. 



The results indicated tliat wliereas tlie radio-active materials benefited, 

 more or less, rape, clover, radishes, and lettuce, they had little or no effect 

 upon peas, tomatoes, nasturtiums, and other flowering annuals. Soils treated 

 with black oxid of uranium in the proportion of 1 part in 2,240 of soil ap- 

 peared, generally, to produce more sturdy plants, but in these cases it was 

 noticeable that the inflorescence was retarded. 



The significance of certain food substances for plant growth, W. B. Bot- 

 TOMLEY {Ann. Bot. [London], 28 (1914), ^^o. Ill, pp. 531-539, figs. 2; abs. in 

 Jour. Cliem. Sac. [London], 106 (WW, No. 626, I, p. 1208).— X considerable 

 fixation of nitrogen by bacterized peat (E. S. R., 31, p. S21) mixed with soil 

 is reported. Experiments with various plants indicated that a water extract 

 of the peat furnished all the plant food required. The residue from the alco- 

 holic extract of the peat, the phosphotungstic precipitate from the aqueous 

 extract, and the fraction (vitamin) obtained by treatment of the phospho- 

 tungstic precipitate with baryta and silver nitrate with the subsequent re- 

 moval of reagents, exerted a stimulating effec-t on plant growth. The effect 

 was especially marked in the case of the vitamin. 



The author advances the theoiy " that the nutrition of a plant depends not 

 only upon the supply of mineral food constituents but also upon a supply of 

 certain accessory organic food substances, very small amounts of which are 

 sufficient to supply the needs of the plant. During the early stages of growth 

 of the embryo, these substances are supplied by the seed; later when the 

 young plant is able to maintain itself, they are obtained from the humus of the 

 soil." Further investigations as to the correctness of this theory are stated 

 to be in progress. 



The question of fertilizers, L. Rebello da Silva (Bol. Dir. Geral Agr. 

 [Portugal], 11 {1912), No. 11, pp. 6Jf). — The whole subject of sources, value, 

 and use of fertilizers is discussed with particular reference to Portuguese con- 

 ditions. The restricted use of fertilizers in Portugal as compared with other 

 countries and the very great importance of extending their use in that country 

 are very strongly emphasized. 



Utilization with special reference to deriving a financial return from the 

 sewage of New York City, G. A. Sopee et al. {Rpt. Mctropol. Sewer. Com. 

 N. T., Wl.'f, pp. 3-'tl-Jfl3). — The report deals especially with sewage farm- 

 ing and with the utilization of sewage sludge. It reviews fully previous in- 

 vestigation and experience and the opinions of authorities in this line through- 

 out the world. The consensus of opinion and experience cited seems to be 

 that the combination of conditions necessary to make sewage farming an effi- 

 cient means of purification rarely occurs and that, as a rule, the interests of 

 agriculture and of sanitation are opposed. 



As regards the utilization of sludge, however, it is concluded that " the 

 revenue to be derived from the sale of dried sludge as fertilizer and from 

 grease will, in many cases, more than offset the cost of production, in large 

 towns, besides furnishing a sanitary and inoffensive method of disposing of 

 sludge. The drying of sludge for fertilizer and the extraction of the contained 

 grease offer a more promising outlook than others. In many works where it 

 would not be worth while to undertake these somewhat elaborate processes, 

 it will be found of advantage to dispose of the semidried, centrifuged, or pressed 

 sludge to farmers for what it will bring or else burn it under the boilers of 

 the plant." 



The mechanism of nitrification, E, M. Mumfoed {Proc. Chem. Soc. London, 

 30 {19U), No. 424, p. 36; ahs. in Chem. A6s., 9 {1915), No. 4, p. 499).— In a 

 study of the bacterial oxidation of aqueous solutions of ammonium salts on 

 experimental filters inoculated from actively nitrifying sewage filters, it was 



