1919] AGRICULTURAL CHEMISTRY — AGROTECHNY. 115 



Evaluation of coconut and palm oils, Vizekn and Guillot (Ann. Chim. 

 Analyt., 2. ser., 1 {1919), No. 4, pp. 111-119). — The authors point out that it is 

 irrational to calculate the acidity of coconut and palm oils in terms of oleic 

 acid, and suggest that the evaluation of the acidity of these oils should be made 

 on the basis of the mean molecular weights of their acids, 208 for coconut oil 

 and 222 for palm oil. 



A revision of the copper phosphate method for the titration of sugar, 

 O. FoLiN and E. C. Peck {.Jour. Biol. Chem., 38 (1919), No. 2, pp. 287-291).— On 

 account of divergent results obtained in the copper phosphate method of Folin 

 and McElIroy (E. S. K., 38, p. 614) for determining sugar, due to variations in- 

 troduced by different individuals in the manner of preparing the salt mixtures, 

 the exact technique for preparing the mixture in order to obtain concordant re- 

 sults is described. This involves flrst mixing the phosphate and thiocyanate 

 thoroughly in a mortar until the thiocyanate has abstracted enough water from 

 the phosphate to give a solution, to which the sodium carbonate is tlien gi*adu- 

 ally added. 



A slight modification of the method is described which is said to eliminate the 

 small loss of copper due to reduction by tlie thiocyanate. Tliis is. accomplished 

 by adding 1 cc. of saturated sodium carbonate to 5 cc. of the copper sulphate so- 

 lution before adding the salt mixture (4 or 5 gm.). This requires the use of a 

 5.9 per cent solution of copper sulphate in place of the 6 per cent solution pre- 

 viously employed. 



A few observations of value in connection with the titration are given, includ- 

 ing certain time restrictions. The modification described is said to be applicable 

 .also to the determination of lactose in milk. 



Analysis of commercial saccharin, I— II, H. D. Richmond and C. A. Hill 

 (Jour. 8oc. Chem. Indus., 37 (1918), No. U, pp. 246T-249T; 38 (1919), No. 2, 

 j)p. 8T-10T). — Two papers are given. 



I. The estimation of o-benzoylsulplionimid from the ammonia produced by 

 acid hydrolysis. — The methods commonly employed for estimating commercial 

 saccharin are discussed, and a method developed as the result of a study of the 

 defects of the present methods is described, the technique of which is as follows : 



Ten cc. of 7.5 N NaOH is boiled for 2 minutes with 0.6104 gm. of saccharin. 

 Fifteen cc. of 10 N HCl is then added and the solution boiled for 50 minutes un- 

 der a reflux condenser. After the heating is completed, 75 cc. of cold water is 

 added and a current of air passed through the upper part of the flask to remove 

 any acid vapor. Fifteen cc. of 7.5 N NaOH is added carefully and the ammonia 

 distilled into an absorption flask, in which is placed 20 cc. of K/5 HCl. After 

 about 70 cc. is distilled, the solution is titrated with N/10 alkali, using methyl 

 red as indicator. 



The method is said to be rapid, convenient, and accurate. 



II. The detection and estimation of impurities. — A discussion is given of the 

 tests in use for determining the impurities of most common occurrence in sac- 

 charin, including moisture, mineral matter, p-sulphonaminobenzoic acid, o-sul- 

 phonaminobenzoic acid, o-toluenesulphonamid, lead and arsenic, melting point, 

 ammonia, easily carbonizable organic matter, sweetness, and the French Codex 

 identification test. 



Determination of the amylolytic power of saliva, L. Grimbekt (Jour. 

 Pharm. et Chim., 7. sen, 19 (1919), No. 8, pp. 2U-250; Compt. Rend. Soc. Biol. 

 [Paris], 82 (1919), No. 9, pp. 312-315), — The author recommends a standardi- 

 zation of the experimental conditions to be observed in determining the amylo- 

 lytic power of saliva in order that results obtained may have a comparative 

 value, and outlines the proposed technique. 



