AGRICULTURAL CHEMISTRY AGROTECHNY. 609 



"Au effort was made to diazotize the different coloring matters, with some 

 encouraging results. The effects of oxidizing and reducing agents were tried 

 and the resulting colors were tested with (1) acids, (2) bases, and (3) salts, 

 and results tabulated. Several oxidizing and reducing agents were tried, 

 among which bromin was found to be the best oxidizing agent and sodium 

 hydrosulphite the best reducing agent. The above scheme of oxidation and 

 reduction, with subsequent treatment with acids, bases, and salts, gave splendid 

 results. 



"The work was-extended so as to include some of the coal-tar colors and 

 also some of the harmless vegetable colors permitted to be used in food prod- 

 ucts. The tables of the results show that natural fruit juice colors can be 

 readily distinguished from each other and from the coal-tar dyes, as well as 

 from the vegetable dyes, in this manner." 



The judging of milk and cream cliocolates, Baier (Ztschr. Angew. Chein., 

 24 {1911), No. 31, pp. 1485, 14S6). — This is a discussion in regard to standards 

 for these confections. 



Coal-tar colors used in food products, B. C. Hesse ( U. S. Depf. Agr., Bur. 

 Chem. Bitl. 147, PP- 228, fig. 1). — The purpose of this work was to determine 

 what members of the synthetic or coal-tar colors ought to be made legal for 

 coloring foods. It contains data in regard to original work done with anilin 

 colors in the Bureau of Chemistry since the passage of the Food and Drugs 

 Act, and also a survey of the literature with special reference to the harmful- 

 ness of these colors. The subject is treated under the following headings : 

 Identity of coal-tar colors used in food products in the United States in 1907 ; 

 purposes of food coloring; food color requirements; conformity of food color 

 market, 1907, to recommendations of the National Confectioners' Association, 

 1899; some legal enactments relative to the use of coal-tar dyes; recommenda- 

 tions by associations and individuals as to use of coal-tar dyes as food colors; 

 recommendations made by the United States color industries and trades to this 

 Department ; investigations, other than on animals, bearing on the harmfulness 

 of coal-tar colors; compilation under the A. G. Green Table numbers of all 

 information available as to the suitability of coal-tar colors for food; dosage 

 and symptoms ; oil-soluble or fat colors ; rules and reasons for selecting the 

 seven colors permitted by F. I. D. 76; lists of colors subsequently recommended 

 by individuals and associations; chemical examination of the 7 permitted 

 colors, 1907; guides in determining degree of purity and cleanliness; analyses 

 of certified lots of permitted colors, 1909-10; and methods of analysis used in 

 testing colors for certification. 



The conclusions drawm are that " coal-tar dyes should not be used indiscrim- 

 inately in foods; only specified coal-tar dyes should be used in foods; [and] 

 only tested and certified dyes should be used in foods." 



The chemical preservatives, H. Serger (Chem. Ztg., 35 (1911), Nos. 121, 

 pp. 1121-1129; 123, pp. 1150-1152; 125, irp. 1166-116S).—A discussion in regard 

 to their uses and detection. 



The determination of benzoic acid, O. Folin and F. F. Flanders (Jour. 

 Amcr. Chem. Soc., 33 (1911), No. 10, pp. 1622-1626). — After numerous experi- 

 ments the authors chose the following procedure : 



Twenty-five gm. of the ketchup in question is weighed out in a 500 cc. beaker 

 and treated with 2 cc. of concentrated nitric acid and well stirred. The bleached 

 mass is transferred to a 500 cc. separatory funnel with 200 cc. of saturated 

 ammonium sulphate solution, and extracted 5 times successively with 50, 35, 

 25, 25. and 25 cc. of chloroform. Violent shaking must be avoided. The chloro- 

 form extracts ore then drawn into a separating funnel containing 200 cc. of a 

 saturated solution of sodium chlorid, which contains 3 cc. of 10 per cent hydro- 



