514 FOODS AND FOOD ADULTERANTS. 



The best class of tallow has a melting-point of about 110 F. Pure 

 tallow requires from 19.3 per cent, to 19.8 per cent, of caustic potash for 

 sapouification, and cotton oil 19.1 to 19.G. A series of mixtures of tal- 

 low and cotton oil was prepared containing 5, 10, 15, 20, 25, 30, and 40 

 per cent, of the oil. The addition of the cotton oil did not have the effect 

 upon the melting-point which might be expected. The pure sfimples 

 melted at 110 F. and the one with 40 per cent, oil at 102 F. The 

 quantity of iodine absorbed was by the pure tallow 40.8 per cent., and 

 by the mixture containing 40 percent, oil 06.2 per cent. The percent- 

 ages for the several samples were as follows: 44,47.1,49.7,52.9,50.1, 

 59.2, 6G.2. The percentage of iodine absorbed by the original cotton oil 

 was 109.1 per cent. The percentages of iodine absorption have a re 

 markably close connection with the percentage of cotton oil present in 

 the various mixtures. 



REACTION OF ANIMAL AND VEGETABLE GLYC BRIDES FOR CHOLES- 

 TERIN AlfD PHYTOSTERIN. 



The presence of cholesterin in animal glycerides, especially liver fat, 

 has long been known. 



A substance homologous with cholesterin was detected in the oil of 

 Calabar beans in 1878 by Hesse, to which he gave the name of phytos- 

 terin.* 



Salkowski proposes to distinguish animal and vegetable fats from 

 each other by testing them for cholesterin and phytosteriu respect- 

 ively t. To obtain the cholesteriu (phytosteriu) 50 grams of the glycer- 

 ides, animal or vegetable are saponified with alcoholic potash. The 

 alcohol is evaporated, and the soap diluted with water to about 2 liters. 

 This is shaken in a separating globe with ether, and the ether solution 

 drawn off and evaporated to small bulk. The residue, which may con. 

 tain a small quantity of unsaponified fat, is again treated with potash, 

 and the separation effected by ether, as above, only a little water being 

 added. If the ether solutions separate slowly, a few drops of alcohol 

 may be added. 



The ethereal extract is evaporated and the cholesterin separated in 

 crystals. Animal cholesterin has a melting-point of 14(5; vegetable 

 (phytosterin) 132. The two also show distinctly crystalline forms 

 which are easilily distinguished under the miscroscope. Vegetal >le 

 cholesterin shows star-shaped crystals or bundles of long, quite solid, 

 needles, while the animal product gives thin rhombic tables. 



Dissolved in chloroform, the two products show different color reac- 

 tions with strong sulphuric acid. Cholesterin shows a cherry-red and 

 pliytosterin ablue-red color. In mixtures of animal and vegetable glycer- 

 ides the melting point of the cholesterin obtained may become a fair in 

 dex of the proportion of the two present. Thus, a melting-point of 13!) 



* An. <l. Cbem. u. Phann., Vol. 19v>, p. 178, 



t Zeitsclirift fiir Analyt ische Chemie, Vol. 20, p. f>7;?. 



