RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Concerning protein, E. PFLLKiKU (Arch, riiyniol. [Pfliiger], 129 (1909), 

 No. 1-2, PI). 99-102). — The author discusses recent work on the cleavage prod- 

 ucts of protein and cautions against drawing sweeping deductions from avail- 

 able data. 



The leucin fraction of proteins, P. A. I.eveni; and D. D. Va?^ Slyke (Jour. 

 Biol. Chem., 6 {1909), No. 5, pp. 391-^18). — According to the authors' experi- 

 ments, " 1-leucin and d-isoleucin may be separated quantitatively from d-valin 

 by precipitation as the normal lead salt, Pb (C6H]202N2). The relative pro- 

 portions of the leucin isomers may be determined polarimetrically by the 

 rotation of their analytically pure mixture in 20 per cent hydrochloric acid. 

 An exact analysis of the important leucin fraction of proteins is thus rendered 

 possible for the first time. . . . Isoleucin preparations from casein and edestin 

 showed, after repeated purification by means of the lead and copper salts, and 

 by recrystallization, specific rotations of -f 37.35° and + 37.44°, respectively, in 

 20 per cent hydrochloric acid." 



The leucin fraction in casein and edestin, P. A. Levene and D. D. V.\N 

 Slyke {Jour. Biol. Chem., 6 {1909), No. 5, pp. 4^9-^30).— Determinations of 

 leucin, valin, and isoleucin from casein and edestin are reported in comparison 

 with earlier work. 



On the partial hydrolysis of edestin, Z. H. Skraup and A. Wober {Monatsh. 

 Chem., 30 {1909), No. 3, pp. 289-309).— From 100 parts of edestin the author 

 obtained 22 parts of acid precipitate (protalbin acid), and 72 parts of albumose 

 (lysalbin acid), 30 parts being peptone (lysalbin peptone). The last two 

 contained ammonium sulphate as an impurity. 



Electrolysis of iron pipe, F. P. Siebel {Ice and Refrig., ,37 {1909), No, 4, 

 pp. 116-119, figs. .'/). — Iron pipes, when immersed in water of good purity and 

 free from Leptothrix ochracea, pitted more readily upon the passage of an 

 electric current. Pipes containing a low amount of carbon corroded much 

 more quickly than those with a high carbon content, but according to the 

 author, the amount of carbon in a metal does not altogether control the condi- 

 tion but rather the distribution of the carbon particles and whether it is present 

 in the free or combined state. Cast irons containing much silicon are also 

 readily decomposed. 



Contributions to micro-chemical analysis, N. Schoorl {Ztschr. Analyt. 

 Chem., .'/8 {1909), No. 10, pp. 593-611) .—Thin further contribution to the subject 

 (E. S. JR., 21, p. 702) treats of magnesium, lithium, potassium, and sodium. 



Nessler's reagent, A. Schneider {Pharm. Zentralhalle, 50 {1909), No. 26, p. 

 546; o&.s'. in Chem. Ztg., 33 {1909), No. 99, licpert., p. 429).— The author calls 

 attention to the fact that frequently Nessler's reagent prepared according to 

 different methods gives no reaction with ammonia, and attributes this to the ab- 

 sence of mercuric iodid which has been removed by filtration. 



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