RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY. 



Biochemical pocket manual, W. Glikin {Biochcmischcs Taschcnhuch. 

 Bciiiiu I'JOD, pp. Xll+J.'fS). — This volume is desigued as a ready reference boolc 

 for biologists, pharmacists, agricultural chemists, students of nutrition, and 

 others. It sunnnarizes a large amount of valuable data arranged systematically 

 under such subheads as air, water, the analysis of foods, condiments and food- 

 stuffs, beer, wine, nutrition, physical data, specific gravity, and percentage con- 

 tent of solutions, reagents, weights and measures, an"d similar subjects. 



The general characters of the proteins, S. B. Schryver {London, Neiv York, 

 and Calcutta, 1D09, pp. X+86; rev. in Lancet [London], 1909, I, No. 23, p. 

 I(i06).- — In this monograph the author considers the physical properties of the 

 proteins, their general chemical character, and biological methods for their iden- 

 tification and ditferentiation. It is his purpose, he states, " to review the chief 

 properties of the proteins, with the object of determining how far they are of 

 value for devising methods of isolation and identification of individual members 

 of the class." 



A bibliography is included in this volume and an index is provided. 



A new method of extracting a phosphorus compound of vegetable origin 

 (phytin), A. Contardi {Atti R. Accad. Lined, Rend. CI. Sei. Fis., Mat. c Nat., 

 5. scr., 18 (1909), I, No. 2, t>p. 6-',-Gl ; aU. in Cheni. Zenthl., 1909, I, No. 13, p. 

 1102). — According to the author's investigations, the phosphorus compounds in 

 plants behave like ordinary esters except that they are more difficultly saponifi- 

 able with alkalis. In the experimental data reported rice brau was heated 

 under pressure with acid, with alkali, and with water alone. 



The determination of iodin in protein combinations, I>. W. RiGciS {Jour. 

 Amer. Chem. Soc, 31 {1909), No. 6, pp. 7iO-7J 7). —According to the author's 

 investigations, " 10 cc. Nessler tubes of clear white glass, and giving a column 

 of liquid 10 cm. in length, yield more delicate readings with dilute solutions of 

 iodin in carbon tetrachlorid than larger sized tubes of a Duboscq colorimeter. 



"A portion of the iodin is oxidized to iodate during the fusion and may be lost 

 unless subse(juently reduced. Devarda's alloy was used as the reducing agent. 

 The reduction is particularly necessary in the analysis of proteins containing 

 but a small proportion of iodin. 



" Excess of nitrous acid fails to reduce iodates so that the iodin can be esti- 

 mated colorimetrically in carbon tetrachlorid solution, and a sufficient excess of 

 nitrous acid will modify or discharge the color of a carbon tetrachlorid solution 

 of iodin. Too great a quantity of sodium nitrate must not be added during the 

 fusion, or an excess of nitrous acid will be formed upon acidifying. 



" Mixtures of protein substances and i)otassium iodid subjected to analysis by 

 the for.egoing process do not give results comparable wuth those obtained from 

 the analysis of a protein substance containing combined iodin, such as thyroid 

 gland tissue." 



517 



