AGEICULTUEAL CHEMISTEY — AGROTECHNY. Ill 



method whether turtle meat (Clenwiys japonica) was adulterated with frog 

 meat {Tyronix japonicus) . 



Determination of cacao shells in cocoa powder, W. L. Dubois and C. I. Lott 

 (Jour. Indus, ami Engin. Chem., 3 (.1911), No. //, pp. 251, 2,52 ) .—According to 

 the authors, the Goske method is faulty and does not indicate with accuracy 

 an addition of less than 5 per cent of cacao shells. See also a previous note 

 (E. S. R., 24, p. 123). 



The detection of prune juice and caramel in vanilla flavoring extracts, 

 W. Denis (Jour. Indus, and Engin. Chem., 3 (1911), No. 4, pp. 25^, 255).— The 

 lead acetate test for detecting caramel in vanilla, according to this author, 

 often yields anomalous results when applied to commercial extracts containing 

 no resins or color soluble in amyl alcohol or ether. Such extracts usually have 

 a high vanillin content. The method was therefore modified and at the same 

 time was made applicable for detecting prune juice in such extracts. It Is as 

 follows : 



" To 25 CO. vanilla extract contained in a 100 cc. beaker add 50 cc. water and 

 evaporate on a steam bath to a volume of 20 cc, filter off the precipitated resins, 

 and wash the filter with about 5 cc. water, the washings being allowed to mix 

 with the filtrate. When cold, place in a small separatory funnel and extract 

 twice with two 15 cc. portions of ether; the color of the first ether extract 

 should always be noted ; the coloring matter of the vanilla bean is fairly sol- 

 uble in ether, caramel and prune juice are absolutely insoluble. Now draw off 

 the aqueous liquid into a beaker and warm for a few minutes on the steam 

 bath to get rid of the last traces of ether, cool, place in a 100 cc. graduated 

 cylinder and add 1 cc. basic lead acetate of specific gravity 1.25, mix by invert- 

 ing the cylinder two or three times and let stand until the precipitate settles. 



" If caramel be present the precipitate will be dark brown in color, while the 

 supernatant liquid will be dark colored also. After the color of the precipi- 

 tate and liquid have been observed, add 5 cc. glacial acetic acid and shake; 

 in the presence of a pure extract, or of an extract colored with caramel, the 

 precipitate will immediately dissolve. If prune juice has been used, there will 

 be obtained on the addition of basic lead acetate to the extract after removal 

 of alcohol, resins, and vanillin in the manner above described a very voluminous 

 dark colored precipitate, while the supernatant liquid will be almost or entirely 

 colorless. On addition of 5 cc. glacial acetic acid to this precipitate it will be 

 found that there is present a lead salt insoluble in acetic acid. This insoluble 

 substance is of a gelatinous reddish-brown appearance, much resembling the 

 precipitate of ferric hydroxid." 



The modified LaWall method for the determination of sodium benzoate in 

 catsups, W. D. McAbee (Jour. Indus, and Engin. Chem., 2 (1910), No. 12, pp. 

 544, 545). — The method as modified by LaWall and Bradshaw was found to 

 be very efficient. 



A source of error in the detection and estimation of salicylic acid, H. 

 Pellet (Ann. Chim. Annlyt., 15 (1910), No. 8, pp. 302-305; abs. in Jour. Che^n. 

 Soc. [London], 98 (1910), No. 516, II, p. 908).— As salicylic acid is a normal 

 constituent of many fruits, and as a substance has been discovered by Backe 

 (E. S. R., 23, p. 306) which gives reactions typical of salicylic acid, the author 

 deems it necessary to determine the quantity of acid present in each article 

 examined. 



-The methods of examining milk and dairy products, C. Babthel (Die 

 Methoden zur Untersuchung von Milch und Molkereiprodukten. Leipsic, 1911, 

 2. ed., rev. and enl., pp. VIII+309, figs. 67). — This is a revision and enlarge- 

 ment of this work, the English edition of which has been noted (E. S. R., 28, 

 p. 513). 



