AGRICULTURAL CHEMISTRY — AGROTECHNY. 313 



Where a nephelouieter is kicking other colorimeters may be adapted to the 

 purpose. In a table a compfii'ison is made of the values obtained with human 

 II nd cows' milk by the method proposed, the Babcock method, and also in some 

 cases the Adams method. " The cows' milk was mixed dairy milk collected 

 from various sources. The human milk samples were from cases in various 

 early stages of lactation and were selected so as to obtain as wide range of 

 fat values as possible." 



A rapid method of estimating fat in cheese, cream, and butter, K. Kropat 

 (.•l/-(7(. J'hann., 252 {1!)J4), A'o. 1, pp. "76-80). — It has been previously shown by 

 Rui)p and Miiller<» that in the estimation of fat in milk the extraction may be 

 facilitated by the addition of gum tragacanth. The method has now been 

 extended to the estimation of fat in cream, cheese, and butter. 



For cheese the procedure is as follows : From 2 to 3 gm. of cheese is heated, 

 with 5 cc. of 25 per cent hydrochloric acid until dissolved. The solution is then 

 treated with from 3 to 5 cc. of alcohol, and after cooling is shaken with 25 cc. 

 of ether. When the separation is complete 25 cc. of light petroleum ether is 

 added and allowed to stand for 15 minutes. Then are added from 1 to 1.5 gm. 

 of gum tragacanth and 3 to 5 cc. of water, and after swelling of the gum the 

 ethereal layer is allowed to separate and the residue washed with light petro- 

 leum ether. The fat is determined in the extract by evaporation in the usual 

 manner. 



A similar method is adopted for cream and butter. 



Material for uniform laws reg'arding foodstuffs. — IV, Cheese (Enticiirfe 

 zu Fc'-stsctzungeri ilher Lehensmittel. — IV, jfiTa-se. Sup. to Ztschr. Untcrsuch. 

 Nahr. u. GenussmtJ., 26 (WIS), No. 6, pp. 30). — Besides describing the various 

 kinds of market cheese, this pamphlet outlines methods for determining the 

 moisture, fat. protein, and ash content of cheese and the detection of the pres- 

 ence of preservatives, such as boric, salicylic, benzoic, and other acids. 



Ethyl ester of linoleic tetrabromid as a product in the analysis of cotton- 

 seed oil, L. S. Palmkb and P. A. Wright (Jour. Indus, and Engin. Chem., 

 6 (191Jf), No. 10, pp. 822, 823). — In the course of some studies on the composition 

 of cotton-seed oil, in which the unsaturated acids were being isolated by the 

 Tortolli and Euggeri method ^ making use of the solubility of their lead soaps 

 in ether and finally recovering the linoleic acid as the tetrabromid, large cluster- 

 ing needles were obtained instead. These needles melted at 58 to 58.5° C. and 

 the crystals showed a much greater solubility in 95 per cent alcohol, glacial 

 acetic acid, petroleum ether, etc., than linoleic tetrabromid. The crystals from 

 all of the solvents were obtained in the same form and had the same melting 

 point, which was strikingly similar to the melting point of the tetrabromid of 

 the isomeric telfairie acid of Thoms. The ethyl ester of linoleic tetrabromid 

 also has a melting point nearly identical with the melting point of the tetra- 

 bromid of the isomeric telfairie acid. 



" The results reported present several points of interest. In the first place, it 

 appears that in isolating the unsaturated acids of cotton-seed oil by the lead 

 soap ether method, some care is required not to allow the lead soaps to stand 

 under ether if the product desired is ordinary linoleic acid or its bromid. In 

 the second place, there is opened up a field of new products of the unsaturated 

 acids, namely, the esters of the bromids. Heretofore esterification has been con- 

 fined to the acids themselves. 



" The authors have prepared a few of these bodies, namely, methyl bromo- 

 linolate and the methyl and ethyl esters of oleic dibromid. They found the 



"Ztschr. Untersuch. Xahr. u. Genussmtl., 23 (1912), No. 7, pp. 338, 339. 

 *Orosi, 23 (1900), No. 1, pp. 109-122. 



