VITAMIN E 347 



to explain this phenomenon by suggesting that in high fat diets the 

 vitamin is taken up by the fat and excreted with the unabsorbed fraction. 



Mattill (1927), attempting to correlate the destruction of vitamin E 

 with that of vitamin A in butter fat or cod-liver oil through oxidation 

 processes accompanied by the development of rancidity, tested several 

 composite rations used in vitamin E studies and also mixtures of simple 

 fats for susceptibility to oxidation by the method of Greenbank and 

 Holm (1925) and found that the presence of wheat germ oil in place 

 of lard in the sterility ration rendered it much less susceptible to oxida- 

 tion, that the rapid oxidation of cod-liver oil was hastened by the 

 presence of traces of ferrous sulfate and retarded by traces of wheat 

 germ oil, that butterfat was less rapidly oxidized than cod-liver oil and 

 that its oxidation was likewise checked by the presence of wheat germ 

 oil. On the theory that the protective action might be due to hydroxyl 

 groups, the acetyl value of wheat germ oil was determined and found 

 to correspond closely to the values for other vegetable oils and to be 

 higher than the values for animal fats and oils, particularly lard and 

 cod-liver oil. The removal of the hydroxyl groups from wheat germ oil 

 by acetylation rendered the oil less effective as an antioxidizer. 



Shortly afterward Evans and Burr (1927c), abandoning their theory 

 of the mechanical removal of vitamin E by excess fat in the ration, 

 reported studies along the same general lines as those of Mattill, sug- 

 gesting the presence in certain fats of a destructive factor for vitamin 

 E associated with the development of rancidity. They found that rather 

 definite amounts of lard, "oleic acid," or any substance capable of 

 neutralizing the effect of vitamin E were required for definite amounts 

 of wheat germ oil as the source of vitamin E. While the destruction of 

 vitamin E was associated with the development of rancidity, even such 

 a good source of vitamin E as wheat germ oil having a definite destruc- 

 tive effect when rancid, the increase in destructive action did not parallel 

 the acid numbers of the fat. In attempts to remove the destructive 

 substance from the fats, it was found that recrystallized lard is less 

 destructive than market lard, and that on neutralizing the free acids in 

 "oleic acid" with potassium hydroxide and extracting the alkaline 

 aqueous solution of the soaps with ether, most of the strong odor and 

 activity are to be found in the ether extract representing the unsaponifi- 

 able fraction. 



Concentration and Attempted Isolation 



The method employed by Evans and Burr in their attempts to isolate 

 vitamin E from wheat germ consists essentially in the following steps: 



