714 EXPERIMENT STATION RECORD. [Vol.40 



A simplification of the McLean- Van Slyke method for determination of 

 plasma chlorids, D. D. Van Slyke and J. J. Donleavy (Jour. Biol. Ghem., 57 

 (1919), No. 4, pp. 551-555). — The authors describe a simplification of the orig- 

 inal McLean and Van Slyke method for the determination of plasma chlorids. 

 This consists essentially in adding picric acid to the standard silver nitrate, 

 the technique then Involving only one filtration and the measurement of an 

 aliquot part of the filtrate for titration. The method is said to be practically 

 identical with the one described by Rappleye (E. S. R., 39, p. SOT), the only 

 difference being the use of iodid instead of sulphocyanate for titrating excess 

 silver. 



The necessity is pointed out of exceptional accuracy in the estimation of 

 plasma chlorids and the calibration of all glass measuring apparatus required 

 for the determination. 



Laboratory manual of Pfister and Vogel Leather Company laboratories, 

 compiled by L. E. Levi (Milicaukec, Wis.: Pfister & Vogel Leather Co., 1918, pp. 

 93). — This manual contains laboratory directions for the preparation of stand- 

 ard solutions and for the analysis of leather and various tanniug materials, 

 oils, soap, urine, various acids, drugs, and dyes. The manual also contains a 

 reprint of the official methods of the American Leather Chemists' Association, 

 and tables of equivalents of standard solutions, chemical factors, and a com- 

 parison of Centigrade and Fahrenheit scab 



The American Leather Chemists' Association, 1918 [Amer, Leather Chetn. 

 Assoc. [By-lans, etc.], 1918, pp. $3). — This is the customary annual, previously 

 1 (E. S. R., 32, p. 314), containing the by-laws of the association; official 

 methods for the analysis of vegetable materials containing tanuin and of vege- 

 table tanned Leather, and for sampling tanning materials; and provisional 

 methods for the analysis of one bath chrome liquors, chrome leather, Bulpho- 

 nated oils, moellons, hard greases, and lactic add. 



Researches on and means to prevent rancidity of vegetable margarin, 

 H. C. Jacobsen (Onderzoekingen Betreffende het Ransig Worden van Planten- 

 boter en de Middelen ter Bestrijding. Oss: Lab. "Ant. Jurgens' Margarine- 

 fabrieken," 1918, pp. 72; abs. in Folia Microbiol. [Delft}, ■'• {1918), So. 2, pp. 

 94-102; Chem. Weekbh, 15 (1918), No. 2',. pp. 757, 753).— The Investigations of 

 Jensen (E. S. K., 14. p. 2S9) on the causes of rancidity of butter and those of 

 Fischer and Gruenert (E. S. R., 26, p. 77S) on the action of preservatives on 

 butter and margarin are reviewed, and similar investigations on vegetable mar- 

 garin are reported. 



The bacteriological studies reported indicate that the rancidity of vegetable 

 margarin is due to the development in the presence of moisture of certain kinds 

 of molds, particularly PcnicilUum glauoum and the yeastlike mold Cludo- 

 sporium butyri. A study of the effect of different preservatives on the growth 

 of these organisms in margarin showed that if salt alone is used from 2.5 to 3 

 per cent is necessary, according to the percentage of water in the margarin. 

 Two per cent of salt was found sufficient with the addition of 0.07.~> per cent 

 benzoic acid, 0.2 per cent sodium benzoate, a mixture of 0.05 per cent benzoic 

 acid and 0.05 per cent sodium benzoate, or a mixture of 0.4 per a :it borax and 

 v.- per cent boric acid. 



The author concludes that rancidity of vegetable margarin can not be pre- 

 vented without the use of preservatives. 



Grain as a source of fat, P. Lindner (Vmsehau, .'. (1918), \ <■'. pp. 63$- 

 636, figs. 6). — The possibility is suggested of utilizing the aleurone cells of 

 grains, such as barley, wheat, and oats, as a source of oil by digesting the cells 

 with dilute hydrochloric acid and extracting l lie oil with ether in a Sorhlet 

 extraction apparatus. 



