522 EXPERIMENT STATION RECORD. 



On the proteid reaction of Adamkiewicz, with contributions to the chem- 

 istry of glyoxylic acid, F. (i. Hopkins and S. W. Cole {Proc. Roy. Soc. [London], 

 68 ( 1901 ) , No. 442, pp. 21-33). — Adamkiewicz in 1874 described the now familiar reac- 

 tion of the production of a violet color when strong sulphuric acid is added to the 

 solution of a proteid in glacial acetic acid. Of late years this reaction has been 

 employed in determining the presence of carbohydrate groups in certain proteid 

 derivatives, though its uncertainty has been several times noted. The authors find 

 from their investigations that the proteid reaction is not a furfurol reaction, but 

 depends upon the presence of small quantities of an impurity in the acetic acid 

 employed, and that this necessary substance is glyoxylic acid. A dilute aqueous 

 solution of glyoxylic acid forms an admiral test for proteids, and may be substituted 

 for the acetic acid of Adamkiewicz' test. 



Nitrites in milk, H. W. Bettink {Nederl. Tijdschr. Pharrn., 13 {1901), jyp. 67-70; 

 abs. in Chem. Centhl., 1901, I, No. 15, p. 854; Jour. Chem. Soc. [London'], 80 [1901), 

 No. 464, LI, p. 422). — The method of Riegler (E. S. R., 9, p. 322) is recommended. 

 To apply this method to milk, 20 cc. is coagulated with 12 drops of strong hydro- 

 chloric acid, filtered, and the filtrate examined in the usual way. 



The examination of market butter, W. von Klenze ( Ztschr. Landw. Versiichsw. 

 Oesterr., 4 {1901), No. 2, pp. 77-80) . — In a comparison of methods of determining the 

 Reichert-Meissl number of butter fat, the author obtained slightly higher results 

 by the use of glycerol-soda solution o\cr the use of alcoholic-soda solution in the 

 saponification. As favorable results were obtained by the use of copper as with glass 

 saponification flasks, while the loss from breakage was eliminated. 



A simple, practical method for estimating the salt content of butter and 

 at the same time indicating the admixture of margarine, B. Orzechowski 

 {Ztschr. Hyg. u. Lnfectionskrcmk., 37 {1901), pp. 275-277; abs. in Chem. Centbl., 1901, 

 IL, No. 3, p. '239). — The method is carried out by treating the butter fat with a solu- 

 tion of alcohol and ether, and allowing the salt to crystallize out from the solution. 

 One gram of butter is rendered soluble in 3 cc. of a weak alkaline mixture of alco- 

 hol and ether in the proportion of 3:7. In testing for the presence of oleomargarine 

 the fat is collected in a glass tube, and if clear is said to be unadulterated. 



A study of the saponification number of fats, O. Schmatolla {Apoth. Ztg., 

 16 {1901), p. 425; abs. in Chem. Centbl, 1901, IL, No. 3, pp. 239, 240). 



Estimation of fat in fodders, M. Jahn {Ztschr. OeffentL Chem., 8 {1901), pp. 

 137-140; abs. in Jour. Chem. Soc. [London], 80 {1901), No. 464, LI, pp. 431,432).— 

 Instead of the usual paper cartridge the author used one made of tin, 70 mm. high 

 and 19 mm. wide, the bottom consisting of brass gauze of 35 meshes to the cm. The 

 gauze is covered inside with a piece of filter paper and a thin layer of cotton wool, 

 upon which the material to be extracted (5 to 10 gm.) is placed and covered with 

 another layer of cotton wool. The ether not being able to escape from the sides must 

 find its way through the mass. With substances containing very little moisture and 

 yielding only a small amount of soluble matter to water or alcohol the previous 

 drying is unnecessary. 



The determination of cocoanut oil in cacao butter and in chocolate, J. 

 Wauters {Bid. Assoc. Beige. Chim., 15 {1901), No. 3, pp. 131, i^i*).— The author states 

 that cocoanut oil is often used to adulterate cacat) butter and chocolate, and proposes 

 a method for determining its presence in the articles named. This is accomplished 

 by his method of determining the addition of cocoanut oil to oleomargarine and 

 butter, i. e., by the determination of the soluble and insoluble volatile acids. 



The determination of sesame oil in chocolate, G. Possetto {Gior. Farm. Chim., 

 51,p>P- 241-245; abs. in Chem. Centbl., 1901, II, No. 3, p. 236). — The determination is 

 made by means of the Baudouin reaction. 



