914 EXPERIMENT STATION RECORD. 



Rapid measurement of potassium bichromate in milk, Gouere (Coinpt. 

 Bend. Acml. iici. [I'aris], 1J,6 (1908), No. 6, pp. 291, 292).— To milk ash dis- 

 solved in cold water is added a solution of potassium iodid and hydrochloric 

 acid. The liquid turns brown, due to iodin liberated. Standardized sodium 

 hyposulphite is added from a burette until the brown color disappears and a 

 blue color, due to chromium salt, is obtained free from yellow. This of itself 

 serves as an indicator for the end point of the reaction. It is advantageous 

 to use a solution of sodium hyposulphite of which 1 cc. is equivalent to 1 mg. of 

 potassium bichromate. 



Analysis of butter for the detection of falsification, D. Crispo {Analyse 

 (III BcKiTc pour hi Recherche de la Falsification. Antwerp, 1907, pp. IJf). — A 

 brief account of tlie methods employed in official examinations in the laboratory 

 of ATitwerp. 



A new constant for butter analysis, T. R. Hodgson (Chem. News, 96 (1907), 

 No. 2J(i<!. pp. 213, 21Ji). — In endeavoring to devise a method of detecting the 

 presence of cocoanut oil in butter the author found the quantity of oxygen 

 required to oxidize a given quantity of saponified butter fat invariable. This 

 constant for butter fat he calls the oxygen equivalent. The method which he 

 describes consists in oxidizing with potassium permanganate the acids obtained 

 from l)utter fat after saponification with caustic potash and acidification with 

 sulphuric acid. 



The oxygen equivalent of cocoanut oil, T. R. Hodgson {Chem. News, 96 

 {1907), No. 2507, p. 288). — The oxygen equivalent of 20 samples of connnercial 

 cocoanut oil, not specially purified, was determined by the method previously 

 described (see preceding abstract). The I'esults for the different samples 

 varied considerably, but the highest value was very much lower than that of 

 butter fat. 



A method for the detection of cocoanut oil in butter fat, T. R. Hodgson 

 {Chem. News, 96 {1907), No. 2508, p. 297).— The oxygen equivalents of mix- 

 tures of butter fat and cocoanut oil, one pure butter fat and one pure cocoanut 

 oil, were determined by the author's method (see preceding extract). The 

 quantity of cocoanut oil in the successive mixtures was increased regularly 

 from 10 to 00 per cent. The results of the tests for the presence of the oil 

 showed an almost constant difference, corresponding to the constant increase 

 in the amount present. In 3 cases the calculated percentage of cocoanut oil 

 agreed exactly with the actual, in 2 it was slightly above, and in 4 it was 

 slightly below the actual amount. 



The dependence of the Polenske number on manipulation, W. Arnold 

 {Pharm. ZentrulhaUe, J,9 {1908), No. 13, pp. 2 37 -2. il).— The author believes that 

 since variations in the Polenske number are so commonly caused by the 

 character of the wire gauze used. e. g., with respect to the size of the mesh or 

 the wire, whether the wire is copper or iron, etc., it is better to discard the net 

 and conduct the distilhition over the free flame. 



The estimation of fat in feces, I.W. Hall {Brit. Med. Jour., 1907, No. 2.',J,6, 

 p. 1399). — A I'apid method of estimating fat in feces is describetl which is 

 especially suitable for clinical purposes. Feces are treated with potassium 

 hydroxid solution made up to definite volume and the fat in an aliquot sample 

 is then extracted in a centrifugal machine or in some other way after treatment 

 with alcohol and hydrochloric acid under the prescribed conditions. 



The microscopy of technical products, T. F. Hanausek, trans, by A. L. 

 AVinton and Kate (1. Barber {New York and London, 1907, pp. XII+J^71, figs. 

 276; rev. in Amer. Jour. Pharm., 80 {1908), No. 1, p. 37). — This is a handbook 

 for the student and investigator of raw materials, with chapters on the micro- 



