EXPERIMENT STATION RECORD. 



Vol. 36. Abstract Number. No. 6. 



RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



The arsenates of lead. — II, Equilibrium in the system PbO, AS2O5, H2O, 

 C. C. McDoNNELX and C. M. Smith {Jour. Anier. Chem. Soc, 38 {1916), No. 11, 

 pp. 2366-2369, fig. i ) .—Continuing the study previously noted (E. S. R., 36, 

 p. 313), it has been shown that the action of dilute ammonia on di-lead arsenate 

 proceeds as follows: "Transposition to tri-lead orthoarsenate, Pbs(As04)a, the 

 supernatant solution remaining constant at the (NH«)2HAs04 stage until 

 transformation is complete. Formation of solid solutions ranging from tri-lead 

 arsenate to a basic arsenate, beyond which no further change occurs." 



Yeast protein, C. Neubebq {Wchnschr. Brau., 32 {1915), No. 38, pp. 317, 319, 

 S20). — The author has isolated several samples of protein from yeast by heat 

 coagulation of an aqueous extract of the dry material. An average sample 

 was found to contain nitrogen 13.02 per cent, sulphur 0.92, and phosphorus 0.59. 



The examination of the pure protein material showed the presence of alanin 

 and tryptophan in the protein molecule, acids not reported by earlier investi- 

 gators. The presence of the alanin suggested it as the source of acetaldehyde 

 encountered in yeast fermentation, and this was verified by experiments 

 carried out with the pure material. 



The organic phosphoric acid of starch, J. H. Nobthbop {Diss., Columbia 

 Univ., 1915, pp. 22). — This material has been essentially noted from another 

 source (E. S. R., 34, p. 710). 



Investigation on the occurrence of chitin and cellulose in bacteria, C. 

 Van Wisselingh {Pharm. Weekhl, 53 {1915), Nos. 33, pp. 1069-1018; 34 pp. 

 1102-1101). — From the results obtained it is concluded that chitin is not in- 

 variably present in bacteria, but often totally absent from the cell-wall material 

 of the micro-organisms. The usual tests for the detection of chitin are deemed 

 unsatisfactory. 



The presence of cellulose was determined in Bacterium xylinum, but it is 

 not considered to occur so commonly as indicated by many investigators. 



The poisonous principle of poison oak (Bhus diversiloba), J. B. McNaioi 

 {Jour. Amer. Chem. Soc., 38 {1916), No. 1, pp. 1^11-1421) .—The results of the 

 investigation reported are summarized as follows : 



The poisonous principle of poison oak {R. diversiloba) is not a glucosid of 

 rhamnose, fisetin, and gallic acid. Syme's* work from which he concludes that 

 the poison of poison ivy {R. toxicodendron) is a glucosid of fisetin, rhamnose, 



^ Some constituents of the poison ivy plant (Rhus toxicodendron). Diss., Johns Hop- 

 kins Univ., 1906, pp. 37; Amer. Chem. Jour., 36 (1906), No. 3, pp. 301-321. 



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