508 EXPEEIMENT STATION RECORD. 



to 1.4 gru. per 100 cc. Coagulable casein dimiuislied very rapidly and at the end 

 of about six months it was about 0.61 per cent. The acidity calculated as lactic 

 acid at the outset was 0.23 per cent and after six mouths it was 0.66 per cent. 



The author believes that a study of other antiseptics should be made with a 

 view of substituting one of them for potassium bichromate. 



The detection of nitrates in milk samples which are treated with potas- 

 sium bichromate, J. dos Santos {Rev. Chim. Piira e Apyl., 8 {1912), pp. 181- 

 184; cbs. ill Chetii. Ztg., 37 {1912), No. Jf, p. //i).— Barium eWorld is recom- 

 mended as a reagent for precipitating the chromate ion. The diphenylamin 

 reaction can then be applied without interference from the chromate. 



About the various methods for determining the moisture content of 

 butter fat, F. Konig (Apoth. Ztg., 28 {1913), No. 7, p. 65).— The methods 

 studied were (1) Soxhlet's in a Soxhlet drying oven with a current of air; 

 (2) Soxhlet's in a wine drying oven but without a current of air; (3) the 

 aluminum dish method; and (4) the indirect method, which utilizes the differ- 

 ence between the total solids and 100. 



The lowest results were obtained by the second and fourth methods, and the 

 highest with the aluminum dish method. In all probability the high results 

 Vvith the Soxhlet' method are due to the removal of volatile fatty acids which 

 may have been present in the butter. While the aluminum dish method is 

 satisfactory for commercial analyses, it is deemed of no value for more exact 

 work. The indirect or difference method is the one preferred by the author. 



The detection of preservatives in fats (butter, margarin, lard), E. Voll- 

 HASE {Chnii. Ztij., 31 {1913), No. 31, p. 312).— The author points out that the 

 Gei-man Imperial Health I>ei>artment (I->. S. It.. 2S, p. 762) and the books on 

 food analysis prescribe methods which are time consuming and require a large 

 amount of material. To overcome these difficulties he evolved a method as 

 follows: Fifty gm. of fat is placed in boiling water containing 1 to 2 drops of 

 15 per cent sodium hydroxid solution and 10 gm. of solid paraffin and shaken 

 thoroughly in order to obtain a fairly uniform distribution of the fat. The 

 mixture is allowed to cool, and if necessary ice used to aid the cooling process. 

 The fat cake is then punctured, the infranatant alkaline fluid filtered through 

 paper, and one-third of the filtrate used for formaldehyde and sulphurous acid 

 tests. The remainder is shaken up with aluminum cream, heated to boiling, 

 and after cooling filtered. A slightly opalescent fluid is thus obtained which is 

 tested for the presence of salicylic, boric, and benzoic acids and their salts, 

 fluorin, and chlorates. 



Estimation of solid fatty acids by Hehner and Mitchell's method, A. 

 Heiduschka and A. Burger {Ztschr. Offeiitl. Chem., 19 {1913), No. 5, pp. 

 87-89; (lbs. in Jour. Chem. Soc. [London], 104 {1913), No. 606, II, p. 351).— 

 The method, which has been previously noted (E. S. R.. 8. p. 861), gives satis- 

 factory results for stearic, palmitic, and myristic acids. When the latter two, 

 however, are to be estimated, they must be dissolved in alcohol to the satura- 

 tion point. If more than 0.5 gm. of palmitic acid is taken for the estimation, 

 the results are too high. " While the presence of acids which are readily solu- 

 ble in alcohol does not interfere with the estimation, it is essential that the 

 particular acid under examination should not be mixed with other fatty acids 

 only slightly soluble in alcohol." 



About the estimation of solid fatty acids according to Hehner and 

 Mitchell's method, H. Serger {Ztschr Offentl. Chem., 19 {1913), No. 7, pp. 

 131, 132, flfj. i).— This is said to be an extension of Heiduschka and Burger's 

 statements noted in the abstract above, and it also includes a description of a 

 filtering and cooling apparatus, which is supposed to increase the efficiency of 

 the method. 



