EDIBLE FATS AND OILS. 



(g) BELFIELDO MICROSCOPIC TEST FOB BEEF FAT. PROVISIONAL. 



147 



Dissolve from 2 to 5 grams of oil or fat in a test tube with about 10 cc of 

 ether, plug the test tube lightly with cotton, and allow to stand 15 or more hours 

 in a moderately cool place. 



The most characteristic crystals are obtained when the crystallization pro- 

 ceeds slowly and at a temperature of 22 to 24 C. The first crop of crystals 

 may be examined and the mother liquor separated and set aside for further 

 crystallization. 



Gladding & has suggested the following procedure to eliminate the olein : 



Dissolve in an Erlenmeyer flask 5 grams of melted fat In 10 cc of absolute 

 alcohol and 5 cc of ether, stopper with cotton, and place in Ice water for about 

 one-half hour, until the more crystallizable portions of the fat have "separated. 

 Separate the crystalline part by filtration through a filter paper moistened with 

 alcohol and wash with the alcohol-ether mixture. After drying in the air for 

 some time dissolve the crystals from the paper by means of ether and then 

 treat as described in the preceding method. When the crystals are ready to 

 be examined remove a drop with a pipette, place on a slide, add a drop of cotton 

 or olive oil, and press a cover glass gently over it. 



TJ. S. Dept. Agr., Division of Chemistry, Bui. 13, Part 4, p. 449 ; Gladding, J. Amer. 

 Chem. Soc., 1896, 18 : 189 ; Wiley, Principles and Practice of Agricultural Analysis, 

 8: 345, 346; Winton, Conn. Agr. Exper. Stat. Kept., 1900, Part 2, p. 145. 



*J. Amer. Chem. Soc., 1896, 18: 189. 



