722 EXPERIMENT STATION RECORD. 



The determination of the total volatile fatty acids in butter, 

 B. W 1; a m pelmbyeb i Landw. I r ers. Stat, 49 {1897), No. 3, pp. 215-218).— 

 The author notes two defects in the Wollny method, i. e., the failure to 

 determine all of the volatile fatty acids and the difficulty of completely 

 removing the alcohol used in saponifying. The latter difficulty has 

 been overcome by the use of glycerin-sodium hydrate as proposed by 

 Leffmanu and Beam. The author has combined this method of sapon- 

 ification with distillation by means of superheated steam. 



The method is as follows : Approximately 5 gin. of Altered fat is 

 saponified in a flask of 700 to 800 cc. capacity with 20 cc. of glycerin- 

 sodinm hydrate 1 by heating over the direct flame, and after frothing 

 has ceased 250 cc. of hot distilled water, previously boiled to expel car- 

 bonic acid, is added with a drop of indicator (litmus) and 50 cc. of sul- 

 phuric acid. 2 The flask is immediately connected with a safety bulb 

 and condenser, and distilled by means of superheated steam generated 

 from distilled and previously boiled water and superheated by passing 

 through a heated copper tube 30 cm. long and 1.4 cm. in diameter. 

 With this apparatus 1£ liters were distilled over in 1| hours, the dis- 

 tillate being collected in 2 portions of 1 and £ liters, respectively. 



The results of a number of determinations in comparison with other 

 methods are given. The author calls particular attention to the neces- 

 sity of thoroughly boiling the water previous to use to expel all carbonic 

 acid, and of preventing by mechanical means any of the alkali going 

 over into the filtrate. The results by the new method were considera- 

 bly higher than those by the Leffmann and Beam method, 5 or 6 cc. 

 more of decinormal alkali per 5 gm. of melted fat being required. 

 This, the author holds, increases the exactness of a determination of 

 the adulteration 15 to 20 per cent, since the numbers for oleomargarin 

 are not higher than those given by the Wollny method. 



The detection of foreign fats in lard and butter, C. B. Coch- 

 ran {Jour. Amer. Chem. Soc, 19 {1897), No. 10, pp. 796-799).— For detect- 

 ing beef fat in lard 2 cc. of melted fat and 22 cc. of fusel oil are heated 

 to obtain a x>erfect solution and then cooled to 16 to 17° C, this tem- 

 perature being maintained for 2 or 3 hours. A crystalline deposit forms, 

 from which the fusel oil is allowed to drain off, and the residue recrys- 

 tallized from ether. "By this method I have been able to detect the 

 presence of a smaller amount of beef fat than I could detect when the 

 sample was directly crystallized from ether." 



Data for 27 samples of lard and fat of various kinds are tabulated. 



For butter or oleomargarin the method is as follows : 



"Add 8 cc. of fused oil to 2 cc. of the filtered fat; warm until a perfect solution is 

 obtained, then cool to lb" or 17° C. A deposit will be formed which, in the few 

 experiments I have made, has been greater in the case of oleomargarin than in 



'Dissolve 100 gm. NaOH in 100 cc. of water and mix 20 cc. of this with 180 cc. of 

 concentrated glycerin. 

 2 Mixture of 20 cc. of concentrated sulphuric acid (sp. gr. 1.84) in 1 liter of water. 



