RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



3Ianual of agricultural and food chemistry, C. Ravenna {Manuale di 

 AnaliHi Chimica Agraria e Bromatoloyica. Bologna: N. Zanichelli, 1914, pp. 

 XMII+360, figs. 28). — Tliis manual of analytical chemistry contains selected 

 methods for the quantitative analysis of soils, fertilizers, mineral constituents 

 of plants, feeding stuffs, fungicides, potable waters, wines, vinegar, edible oils 

 and fats, milk, butter, cheese, and flour. An appendix contains directions for 

 the preparation of reagents and various tables to be used in connection with 

 the analytical methods described. 



Continuation and extension of work on vegetable proteins, T. B. Osborne 

 and L. B. Mendel {Carnegie Inst. Washington Year Book, 17 {1918), pp. 302- 

 310). — This is the progress report for 1918 in continuation of work previously 

 noted (E. S. R., 40, p. 463). The investigations outlined have been noted for 

 the most part from other sources. 



[The urease content of seeds], D. H. Wester {Cheni. Weekbl., 16 {1919), 

 No. 51, pp. I.').'f8-lf}56). — Two papers are presented. 



I. The urease content of domestic seeds (pp. 1548-1551). — The urease con- 

 tent of 46 varieties of seeds was determined by the effect of glycerin extracts 

 of the seeds upon known amounts of urea. 



The seeds varied widely in their urease content, 15 showing no traces of 

 urease and the others widely varying amounts as determined by enzym 

 activity. This was true not only of different families but of different species 

 in the same family. The highest enzym activity next to the soy bean and 

 Canavalia was found in the seeds of Cytisus laburnum, Oeranium molle, Vicia 

 •silratica, and Lupimis luteus. 



II. The urease content of different varieties of soy beans (pp. 1552-1556). — 

 Determinations by the method noted above of the urea content of about 48 

 varieties of Asiatic and African soy beans are reported. All of the beans, 

 whether old or fresh, possessed strong enzym action. 



The adjustment of the reaction of bacteriological media, J. McIntosh 

 and W. A. M. Smart {Lancet [Londo7i], 1919, II, No 17, pp. 723-726, flg. 1).— 

 This is a brief report of an investigation of the various processes of adjusting 

 the reaction of bacteriological media, as a result of which the author concludes 

 that, with certain precautions, the titration method is not only a reliable 

 method of adjusting the reaction in routine practice, but by means of a specially 

 prepareil graph it can be used also to indicate pH values. Titration of the media 

 at room temperature instead of at the boiling point is recommended on account 

 of possible dissociation of the complex organic compounds of the media at 

 higher temperature. Thymolphthalein is considered the most suitable indicator 

 for titration on account of the sharpness of the end-point. 

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