t EXPERIMENT STATION RECORD. 



Vol-. 43. Abstkact Numuer. No. 3. 



RECENT V/ORK IN AGRICULTURAL SCIENCE. 



AGRICTJLTTJEAL CHEMISTRY— AGROTECHNY. 



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nP The chemists' year book, 1 9 18-1!), F. W. Atack and L. Wiitnyatks 

 (London: Shcinitt <( llnnhcH, 19Ji), J,, cd., vola. 1, pp. Hi]-\-J,22, fiys. 8; 2, pp. 

 Wi +423-1146, Jijjs. ;.'/).— The fourth etlition (1918-19) of this year hook of 

 chemistry contains, in addition to revisions of a general cliaracter, new sections 

 on Analysis of Clays, Firebricks, and Silica Rlaterials by J. W. IMellor, and on 

 Atrricultural Chemistry by E. .T. Kussell ; and revisions of the sections on Dairy 

 Products by (}. 1). FIsdon and A. D. Ileywood, Crystalloiirapliy by E. II. Kodd, 

 Electroclioiiiistry by F. M. I'erkins, Water Analysis by 1 >. K. Davey, I^ropcrties 

 of Essential Oils by L. (i. Kadcliffe, 1'aniiin Materials by W. iMather, and Alka- 

 loids i)y E. Hope. 



Proj>ress in fat chemistry in If) 18, W. Faukion {Clicin. Umschau Geb. 

 Fettc, Ovlc, Wiicltac, u. llurze, 20 (lUlU), Nos. 16, pp. ]<)7-199; 17, pp. 209-211; 

 IS, pp. 221-223). — This is a review of the literature on theoretical (iip. 197- 

 199), analytical (pp. 209-211), and technical (pp. 221-223) fat chemistry. 



The rancidity of IMiilij)pinc coconut oil, G. A. Pekkins {Philippine Jour. 

 Sci., lo {1919), No. 5, pp. 463-.'f74)- — 'J'lie conceptions of various authors con- 

 cerning the cause and nature of the rancidity of oils, including the recent work 

 of Drill and I'arker (E. 8. R., 39, p. lOS), are reviewed, and experiments are 

 reported in whicii the relative effect of various factors in the deveb)pment of 

 rancidity in edil>le coconut oil was determined. The rancidity factors studied 

 were initial acidity, air, light, moisture, and the enzyms and nonfatty material 

 present in the oil obtained by' expression. The tests for rancidity included 

 acidity determinations, iodin number (Hanus), fuchsin-aldehyde test, oxidiza- 

 bility value by a slight modilication of the Issoglio test (E. S. K., 37, p. 114), 

 and odor, l-'rom the analytical data obtained the following conclusions are 

 drawn : 



"In the type of rancidity of coconut oil studied, the lirst stage is a hydroly- 

 si.s, the rapitlity of which varies with the initial aci-dity and the amount of 

 moisture present. Exclusive of any mold action, this hydrolysis may be some- 

 what accelerated by the action of air, light, and a fat-soluble enzym. The second 

 stage of rancidity is an oxidation of the free fatty acids. I'o.ssibly this in- 

 volves also the oxidation of unhydrolyzed olein, but the amount of oxidation 

 Is dependent on the amount of hydrolysis. The oxidatii)n is hastened by light 

 ai;d moisture, but light is not a necessary condition." 



As tests to deterniint! the amount of deterioration in oil umb'rgoing tbe 

 '•rdinary type of rancidity, the author reconnnends the iodin number, the 

 ^luchsiu-aldehyde lest, and the oxidizability, 

 wk 201 



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