EXPERIMENT STATION RECORD. 



Vol. 35. Abstract Number. No. 3. 



RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTUEAL CHEMISTRY— AGROTECHNY. 



Annual reports on the progress of chemistry for 1915, edited by J. C Cain, 

 A. J. Gkeenaway, and C. Smith (Ann. Rpts. Prog. Chem. [London], 12 (1915), 

 pp. VIII-\-268, figs. 6). — This report deals with the progress made during the 

 year 1915 in the subjects listed in reports previously noted (E. S. R., 35, p. 8). 



The preparation and composition of caseinogen, J. Meu^lanby (Biochem. 

 Jour., 9 (1915), No. 3, pp. 342-350). — The author uses the word caseinogen to 

 denote the main protein present in milk; acidic caseinogen, the protein pre- 

 cipitated from milk by acid ; and casein, the protein precipitated from milk by 

 the action of proteolytic ferments and calcium salts. 



A method for the precipitation of caseinogen from milk by alcohol is described 

 in detail, together with experimental data as to the calcium and phosphorus 

 content of caseinogen and of acidic caseinogen. 



The results of the analyses of caseinogen and acidic caseinogen indicate that 

 caseinogen is composed of a complex of one unit of protein and a molecule of 

 tricalcium phosphate. The precipitation of acidic caseinogen from caseinogen 

 by acetic acid is expressed by the formula 



Protein, Gas (P04)2+6HA=Protein, GHA+Caa (PO*), 

 ( caseinogen ) ( acidic caseinogen ) . 



A note on iodized protein, A. Oswald (Hoppe-Seyler's Ztschr. Physiol. Chem., 

 95 (1915), No. 5-6, pp. 351, 352). — The author describes a procedure for the 

 preparation of an iodized casein. This contains 14.39 per cent iodin, is pure 

 white in color, and is not affected by the action of even the direct rays of 

 sunlight. 



A colorimetric method for the estimation of amino-acid a-nitrogen, — II, 

 Application to the hydrolysis of proteins by pancreatic enzyms, V. J. Hard- 

 ing and R. M. MacLean (Jour. Biol. Chem., 24 (1916), No. 4, pp. 503-517, figs. 

 8). — The colorimetric method previously described (E. S. R., 34, p. 505) has been 

 experimentally applied to a study of the rate of proteoclasis of casein, serum 

 albumin and globulin, peptone, nucleoprotein, gluten, fibrin, and gelatin by 

 pancreatic enzyms. The results were compared with those obtained by the 

 Sorensen and Van Slyke methods, and agreed very well with those from the 

 Van Slyke but not from the Sorensen method. 



The composition of " lecithin," together with observations on the distri- 

 bution of phosphatids in the tissues and methods for their extraction and 

 purification, H. MacLean (Biochem. Jour., 9 (1915), No. 3, pp. 351-378).— 

 Phosphatids extracted from tissues by alcohol invariably contain large amounts 

 of a nitrogenous impurity which is very difficult to remove by any of the 



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