340 THE VITAMINS 



whole milk powder as the sole food furnished adequate amounts of 

 vitamin E in Evans' experiments. Of butterfat, 9 per cent of the ration 

 is usually insufficient to secure fertility, but with rations containing 

 much larger amounts fertility results. Conflicting evidence on the 

 presence of vitamin E in butterfat can probably be explained by the 

 destruction of the vitamin to a greater or less extent by other con- 

 stituents of the diet. As is to be expected from the relatively low content 

 of vitamin E in the viscera, cod-liver oil is extremely low though not 

 entirely lacking in vitamin E. 



In contrast with the low content of vitamin E in animal tissues is 

 its high concentration in the organs of certain plants, especially in 

 green leaves and seeds. The richest known sources of vitamin E are 

 lettuce leaves and wheat embryo, both of which remain active when 

 desiccated. Successful curative tests have been made with amounts as 

 small as 250 milligrams daily of dried lettuce powder and smaller 

 amounts have been partially successful. Alfalfa leaves and even tea 

 leaves have been found to be fairly rich in vitamin E, although not 

 so rich as lettuce. Daily doses of 1 gram of peanuts or 5 grams of corn 

 embryo, alfalfa seed, and lettuce seed were curative in the experiments 

 reported by Evans and Burr. 



Most vegetable and seed oils contain vitamin E, but in not very 

 high concentration. In curative tests (which always require considerably 

 more of the vitamin than prophylactic tests) 100 milligrams of cotton- 

 seed oil, olive oil, walnut oil, peanut oil, and flaxseed oil were without 

 effect, although some of these oils were effective in smaller dosage in 

 prophylactic tests. Evans and Burr are of the opinion that all of these 

 oils contain enough vitamin E to confer fertility if they could be fed 

 in amounts representing the total fat content of the ration. In one trial, 

 cures resulted from the feeding of walnut oil to the extent of 22 per 

 cent of the ration. It is of interest that lettuce-seed oil was effective 

 in dosage of 160 milligrams daily, representing one-half gram of 

 seed. 



The only fruits tested by Evans and Burr were bananas and oranges, 

 both of which contained the vitamin but in very low concentration. 

 About 27 grams daily of banana and from 8 to 16 cubic centimeters of 

 orange juice were employed in curative experiments which, in the case 

 of the orange at least, were only partially successful. 



Sure has reported from time to time on the occurrence of vitamin 

 E in various food materials, his results (although obtained with differ- 

 ent basal rations and technique) corroborating in a general way those 

 of Evans. Sure (1924b) reported the presence of vitamin E in the 



