AGRICULTURAL. CHEMISTRY — ^AGROTECHNY. • 805 



rice, wheat, rye, barley, and oats can be taken as 183 or 183.4°. Before sac- 

 charification the authors advise, when examining feeding stuffs or other starch- 

 containing materials with the polarimetric method, washing these samples with 

 water, alcohol, and ether for the purpose of removing foreign substances 

 which may be optically active. The polarimetric method can also be em- 

 ployed for cacao, cinnamon, pepper, etc. See also previous notes (E. S. R., 22, 

 pp. Ill, 30G: 24, p. 11). 



Determination of gelatin, W. Geeifenhagen, J. Konig, and A. Scholl 

 (Biochem. Ztschr., 35 {1911), No. 3-Jf, pp. 2i7-227).— The authors point out 

 that the Beckmann method for the determination of gelatin does not yield re- 

 sults which are of practical value. They find that the Vamvakas method, in 

 which the gelatin is precipitated with Nessler's reagent in an acid solution, 

 will yield quantitative results for gelatin, but a separation of gelatin from 

 proteoses when the latter are present is not possible. Proteoses are not pre- 

 cipitated quantitatively, but the method can be employed as a qualitative test. 

 An excess of trichloracetic acid, as employed by Obermayer, yields only a tur- 

 bidity in dilute gelatin solutions, and also does not precipitate the proteoses 

 quantitatively. Corrosive sublimate produces no precipitate in a neutral solu- 

 tion of gelatin, but yields a precipitate of proteoses. 



Nothing more than the approximation of the gelatin content of jellies, mar- 

 malades, etc., can be expected from the above-mentioned methods. 



Advances made in the chemistry of bee honey during- 1911, A. Hasterlik 

 {Leipzig. Biencn Ztg., 27 {1912), No. 2, pp. 19-23). — A review of the literature. 



The detection of olive husks in pepper, C. V. Garola and V. Braun {Ami. 

 Falsif., 4 {1911), No. 35, pp. 467-Ji69, figs. 2).— A discussion of methods, with 

 particular regard to the use of the polarizing microscope for detecting adultera- 

 tions in pepper. 



Determination of tartaric acid in cider, perry, vineg-ar, etc., A. Kling and 

 L. Gilbert {Ann. Falsif., 1/ {1911), No. 30, pp. 185-192). — Two ciders examined 

 by this method (E. S. R., 23, p. 418) showed 4.02 per cent and 3.22 per cent of 

 tartaric acid respectively. Of 2 perries 1 gave a negative result, while the sec- 

 ond contained 1.97 per cent of tartaric acid. The results obtained in most in- 

 stances were higher than those obtained with the ether-alcohol method. The 

 method can also be applied to the examination of vinegar and kindred products 

 (see below). 



Estimation of tartaric acid in apples, pears, cider, and perry, G. Warcol- 

 LiER {Ann. Falsif., 4 {1911), No. 35, pp. 485-/,90; abs. in Analyst, 36 {1911), No. 

 .'{28, pp. 5-'i5, 546). — The author sought to apply the Kling method to the estima- 

 tion of tartaric acid in apples and pears and their products. Neither the 

 apple, pear (ripe or unripe), nor the cider or perry therefrom showed a trace 

 of tartaric acid. 



Kobert's reagent as a test for salicylic acid, J. McCrae {Analyst, 36 {1911), 

 No. 428, pp. 540, 541)- — This reagent, which consists of 3 drops of formaldehyde 

 solution in 3 cc. of sulphuric acid, when added to salicylic acid or its salts, gives 

 a rose-red coloration. The color, however, does not appear immediately. The 

 same result is obtained with aspirin (acetyl-salicylic acid) and salol, but in the 

 case of the latter the color develops much more quickly. 



" Robert's reagent gives the following characteristic colors with other sub- 

 stances: Phenol, red-violet; catechol, violet (redder than the morphin color); 

 resorcinol, deep orange-brown ; quinol, dirty greenish-brown ; pyrogallol, brown ; 

 a-naphthol, dirty green ; /3-naphthol, dirty brown ; cinnamic acid, brown ; man- 

 delic acid, yellow." 



[Analysis of milk and wine] {Mitt. Lchensm. JJntersuch. u. Hyg., Schweis. 

 Osndhtsamt., 2 {1911), No. 7, pp. 425-J,80). — This is a description of the revised 



