506 EXPERIMENT STATIOX EECOBD. 



contents of the separatory funnel are shaken out with ether. The combined 

 portions of the ether solution are filtered and evaporated to dryness on the 

 water bath. The residue is next talien up with about 25 cc. of fat-free petro- 

 leum ether (boiling point 30 to 50° C), and about 10 or 15 cc. of 95 per cent 

 alcohol is added. This is titrated with twentieth-normal allvali, using about 



2 drops of a 1 per cent solution of phenolphthalein as indicator. The end 

 point is sharp and distinct." 



Concordant results of the fat content of blood, liver, and clear back fat of 

 pork were obtained, which was not possible with the Soxhlet or Kumagawa- 

 Suto * methods. 



Experimental and critical contributions to the examination of foods 

 (Exijcrimentelle und k7-itische Beiirdge zur Neubearbcituny dcr Vereinbaningcn 

 zur cinheitlichen Untersuchung und Beurteilung von Nahrungs- und Gentmsmit- 

 tcln soicie Gebrauchtsgegenstiinden fiir das Deutsche Reich. Berlin: J. Springer, 

 1911, vol. 1, pp. VI+266, figs. 12; 1914, vol. 2, pp. VIII+306, figs. 4).— This is a 

 collection of reprints of investigations by various authors on food analysis and 

 detection of adulterants, issued by the Imperial Health Service (Kaiserlichen 

 Gesundheitsamte) . 



The determination of starch in raw potatoes, E. Ewebs (Ztschr. Offentl. 

 Chem., 21 (1915), No. 15, pp. 232, 233). — The author describes two procedures 

 for the preparation of the sample for analysis. Methods for determination of 

 the starch with the polariscope, (1) by dissolving the starch in liot dilute hydro- 

 chloric acid and (2) by dissolving the starch in cold concentrated hydrochloric 

 acid, are described in detail. 



The determination of glycerin in wine, F. Wohack (Ztschr. Landw. Ver- 

 suchsw. Osterr., 17 {19W, No. 8-9, pp. 684-697, fig. i).— The author describes 

 a modified apparatus and proce^lure for the determination of glycerin in wine, 

 based on the principle of the Klemenc method. Concordant results have been 

 obtained and the procedure is recommended as being the least expensive thus 

 far proposed. 



Note on the determination of milk fat, A. M. Wright (Tran-s. and Proc. 

 New Zeal. Inst., -J7 (1914), PP- 572, 573). — A series of fat determinations on 

 fresh milk, comparing the official Adams and the Gottlieb methods, were car- 

 ried out. The Gottlieb method was found to give consistently higher results. 



Note on the use of colloidal iron in the determination of lactose in milk, 

 R. L. Hill (Jour. Biol. Chcm., 20 (1915), No. 3, pp. 175-177).— The use of a 10 

 per cent solution of colloidal iron (dialyzed ferric hydrosid) is recommended 

 as a protein precipitant. The method is as follows : 



" To a 10-gm. sample of milk which has been diluted to about 25 cc, about 



3 cc. of a 10 per cent solution of colloidal iron is added. The amount of colloidal 

 iron necessary depends upon the composition of the milk and can be accurately 

 determined by adding the last portion drop by drop, and agitating after each 

 addition. If the precipitation is complete, a clear supernatant liquid separates 

 out from the flocculeiit precipitate; if too little has been added, the supernatant 

 liquid will appear milky ; if too miich, it will have a reddish tinge. The .sample 

 is next filtered into a 100 cc. volumetric flask, and the precipitate thoroughly 

 washed with distilled water until the filtrate and wa.shings aggregate about 100 

 cc. The flask is then filled to the mark and the percentage of lactose determined 

 by Benedict's quantitative method [E. S. R., 2.5, p. 15]. About 16 cc. of the 

 diluted sample will be required to reduce completely 25 cc. of Benedict's quanti- 

 tative solution." 



1 niochem. Ztschr., 8 (1908), No. 2-4, pp. l>]L'-347. 



