VITAMIN E 339 



may be destroyed by the oxidizing action of other constituents. As 

 Mattill (1927) has stated: 



"Depending on the presence of catalysts of various kinds, or of antioxidizers, 

 the amoimt of \-itamin E present in an indivndual foodstuff or in ration mixtures 

 remains unimpaired for shorter or longer periods. WTiether the oxidative changes 

 that condition its destruction may take place in the alimentary tract after the 

 ration has been consumed, as well as during its preparation or in containers 

 before its ingestion, remains to be determined. Ob\'iously the assay of foodstuffs 

 for their content of \-itamin E has been a resultant of (.1) tiae actual amount of 

 E present and (2) the kind and amount of antioxidizers associated with it." 



The most extensive studies of vitamin E distribution are those of 

 Evans and his associates as summarized in the University of California 

 Memoir by Evans and Burr (1927d). 



In their earlier studies E\-ans and his collaborators used as their 

 basal ration a mixture consisting of casein 18, cornstarch (cooked and 

 subsequently dried) 54, lard 19, milk fat 5, and salts 4 per cent, with 

 dried whole yeast from 0.4 to 0.6 gram daily. Later this diet was 

 changed to one consisting of casein 32, cornstarch 40, lard 22, cod-liver 

 oil 2, and salts 4 per cent, with the same amount of yeast. The salt 

 mixture in both cases was McCollum mixture No. 185, consisting of 

 sodium chloride 51, cr^'stals of magnesium sulfate 159.6, monobasic 

 sodium phosphate 104.1, monobasic calcium phosphate 162, dibasic 

 potassiimi phosphate 2S6.2, ferric citrate 35.4, and calcium lactate 390 

 parts. 



In Evans' opinion female rats to be used in detecting the presence 

 of \-itamin E should not only show the typical signs of \-itamin E de- 

 ficiency on breeding — implantation of the ovum, but eventual resorption 

 of the fetus — but should give evidence of normal fertility when tested 

 with a material of proven potency in vitamin E. Curative tests are con- 

 sidered much more reliable than prophylactic. The test, therefore, con- 

 sists in establishing resorption gestation on the basal ration alone and 

 subsequent fertility on the basal ration supplemented by the material 

 in question, the amount required in comparison with a standardized 

 source of vitamin E such as wheat germ oil being a measure of the 

 richness of the material in vitamin E. 



With the use of the method as briefly sketched, Evans and his col- 

 laborators (see Evans and Burr, 1927d) have shown that \itamin E 

 is present, but never in high concentration, in a great variety of animal 

 tissues. In contrast with vitamin A, it is more abundant in the general 

 body musculature and fat than in the viscera. \'itamin E is present in 

 egg yolk and in milk, the amoimt in the latter being higher in pasture- 

 fed than stall-fed cattle. In contrast with Mattill's results with milk. 



