612 EXPERIMENT STATION RECORD. 



A polariscopic method for the determination of malic acid and its applica- 

 tion in cane and maple products, P. A. Yoder (Ahs. in Science, n. ser., 32 

 {1910), No. 823, p. 478). — "Making use of the fact that uranyl compouuds 

 cause a manifold increase in the optical activity of active dicarboxylic hydroxy 

 acids, the author has developed from extensive original data a method of 

 estimatuig malic acid in solutions which may at the same time contain a wide 

 range of other substances." 



Eeport on the progress of the chemistry of milk and dairy products for 

 the first half year of 1910, Grimmer {Idilchiv. Zentbh, 6 {1910), No. 8, pp. 

 337-352 ) . — ^This is a retrospect of the progress made in the field of the chemis- 

 try of milk and dairy products. 



Methods for detecting heated milk in dairy products, particularly in butter, 

 Hesse and D. W. Kooper {Milchw. ZentU., 6 {1910). No. 9, pp. 412-^20).— The 

 results show that the most sensitive reagents are Storch's paraphenylendiamin 

 (E. S. R., 10, p. 384), and the guaiacol-paraphenyleudiamin tests (E. S. R., 

 20, p. 1107 ) , preference being given to the latter. See also the work of Wilkin- 

 son and Peters (E. S. R., 20, p. 1108). 



Detecting milk which has been heated, Hesse {Molk. Ztg. [Hildesheim], 

 24 {1910), No. 99, pp. 1857, 1858). — Noted above from another source. 



The refractometry of the chlorid of calcium serum of milk from individual 

 cows, C. Mai and S. Rothenfusser {Ztschr. Untcrsuch. Nahr. u. Genussmtl., 

 21 {1911), No. 1, pp. 23-37; Molk. Ztg. Berlin, 21 {1911), Nos. 5, pp. 50, 51; 

 G, pp. 62-64). — ^^^s a result of examining the milk of individual cows by this 

 method (B. S. R., 23, p. 809) the authors conclude that it is without doubt an 

 accurate means for detecting added water to milk, even where the milk itself 

 undergoes natural variations in its composition. 



In regard to the refractometi^ of calcium chlorid milk serum, G. Fend- 

 ler, C. Borkel and W. Heidemeister {Ztschr. Untersuch. Nahr. u. Oenussmtl., 

 20 {1910), No. 3, pp. 156-169; aJ)s. in Chem. Ztg., 34 {1910), No. 145, Repert., 

 p. 598). — The authors deduce from their results of the examination of a large 

 number of milk samples for the refraction and specific gravity of the calcium 

 chlorid milk serum that no relation seems to exist between these constants 

 nor between either one of them to the fat-free dry substance of the milk. 

 See also a previous note by Mai and Rothenfusser (E. S. R., 23, p. 309). 



Detection of peanut oil in cotton-seed and other oils, S. Fachini and G. 

 DoRiA {Ais. in Chem. Ztg., 34 {1910), No. 112, p. 99-}).— The method differs 

 from that of Tortelli and Ruggeri (E. S. R., 11, ix 23) in that acetone is 

 employed instead of ethyl alcohol for removing the arachidic acid and the 

 soluble and insoluble fatty acids. Acetone has several advantages, which 

 are stated. 



Quantitative determination of water in pastes, semipastes, and mixed 

 paints, L. P. Nemzek {North Dakota Sta. Spec. Bui. 28, pp. 254, 255).— A 

 method is described which differs from the one generally used for this pur- 

 pose, inasmuch as it requires less time for its execution and determines only 

 the free water incorporated in the paint without that in combination with 

 the color. See also a note by Sadtler (E. S. R., 23, p. 112). 



The method is conducted as follows : " Weigh 100 gm. of the thoroughly mixed 

 sample into a 250 cc. Erlenmeyer or side-neck distilling flask. Add about 

 90 cc. of toluol previously dried with calcium chlorid. Shake gently until a 

 uniform mixture is obtained. Distill over 60 to 75 cc. into a suitable graduate. 

 The percentage of water, if there be any present, can be read direct from the 

 graduate. For convenience and accuracy the graduate should be calibrated 

 to tenth of cubic centimeters. The determination should be made at 95 to 



