530 EXPERIMENT STATION RECORD. 



No. 12, pp. 705-726). — Different commercial yeasts and pure cultures were studied 

 with special reference to the examination of sirups. In the author's opinion, since 

 pure cultures can not always be obtained in all laboratories, beer yeast may be used 

 and will give satisfactory results in the estimation of dextrin. When it is desirable 

 to determine maltose in addition to glucose and dextrin, wine yeast may be used. 



A new indirect method of determining- aldehyde in lemon oil, E. Berte 

 (Chem. Ztg., 29 (1905), Xo. 60, pp. 805, 806).— The method depends upon the differ- 

 ences noted with the polariscope in liquid lemon oil before and after it has been acted 

 upon by potassium bisulphite, as in the method previously described by Berte and 

 Soldaini." 



The estimation of the fusel oil of alcoholic liquors, E. Beckmann (Ztschr. 

 fyitersuch. Nahr. u. Genussmtl, 10 (1905), No. 1-2, pp. 143-152) .—Improved methods 

 of estimating fusel oil are described. 



Contribution to our knowledge of the action of pepsin, with special refer- 

 ence to its quantitative estimation, P. W. Cobb (Amer. Jour. Physiol, 13(1905), 

 No. 5, pp. 448-46-1, jitf*. 3).— A study of the comparative merits of different methods 

 for the quantitative estimation of pepsin is reported. Some of the conclusions which 

 were drawn follow: 



"Making all due allowances for errors due to the [Metts] method itself, pepsin 

 solutions capable of digesting 4 mm. or over in 24 hours give results far below 

 those anticipated by the rule of square roots from the amount of pepsin present. No 

 calculation can be made in any case as to the absolute or relative pepsin values until 

 the question of inhibition is eliminated. Commercial pepsin sometimes contains con- 

 siderable amounts of inhibitory substance, evident in solutions of -fa per cent strength. 

 And in regard to the albumin-froth method of Bettman and Schroeder: Results 

 obtained by it can not be justifiably expressed in figures indicative of pepsin-concen- 

 tration, but only by such expressions as 'strong,' 'very strong,' 'moderate,' etc." 



The estimation of boric acid, W. VAUBELand E. Bartelt ( Chem. Ztg., 29(1905), 

 Xo. 46, pp. 629, 630). — The detection of boric acid with curcuma paper and its esti- 

 mation by the Jorgensen titration method are discussed on the basis of personal 

 experience. 



Among other precautions the authors note that the Jorgensen method does not give 

 satisfactory results when phosphoric acid is present and that sulphurous acid must 

 be removed before the method can be applied. Any strong acid other than boric 

 should be neutralized, and when this is done methyl orange may be used as an 

 indicator. 



Modification of Hehner's test for formaldehyde, A B. Lyons (Pharm. Jour, 

 [London], 75 (1905), p. 443; abs. in Jour. Soc. Chem. Indus., 24 (1905), Xo. 20, 

 p. 1086). — In using Hehner's test for the detection of formaldehyde in other solutions 

 than milk, the author recommends the addition of beef peptone instead of milk and 

 states that this test is capable of detecting 1 part of formaldehyde in 4,000,000. 



Strychnin tannate and its use in the analysis of tanning materials, S. R. 

 Trotman and J. E. Hackford (Jour. Soc. Chem. Indus., 24 (1905), Xo. 21, pp. 1096- 

 1100, fig. 1). — Objections to the hide powder method and the collin method of 

 Parker and Payne for tanning materials are pointed out, and a method based upon 

 the precipitation of tannic acid with strychnin sulphate is described. 



The use of the electric current in quantitative determinations in food 

 analysis, G. Rupp (Ztschr. Untersuch, Nahr. u. Genussmtl., 10(1905), No. 1-2, pp. 

 37-41). — A paper with discussion presented before the meeting of German Food 

 Chemists in Dresden, 1905. The method proposed depends upon the resistance of 

 different liquids to the passage of an electric current, 



"Chem. and Drug., 1903, Sept. 



