Preparation and Properties of Vitamin E Concentrates*

Various observations necessarily made on vitamin E concentrates in connection with work on purification of vitamins (l), while outside the scope of that paper, disclosed many pitfalls which the experimenter may avoid with the information here presented. If certain simple precautions are not taken during extraction and saponification of the wheat germ oil, losses of over 90 per cent of its vitamin E activity are often found. Testing of Fractions with Rats-In testing for vitamin E, female rats reared on a diet’ low in vitamin E were always first proved sterile by mating, appearance of the “erythrocyte sign” about 13 days later, and failure to produce a litter. The fractions to be tested were fed on the 2nd day of the next gestation period; the details of the test have been described elsewhere ((3) pp. 2, 53). Birth of living young was used as the criterion that vitamin E was present, while resorption of the young indicated that there was less than a rat unit of vitamin E in the amount of fraction fed. When exactly 1 rat unit has been fed, there will be fewer animals per litter than with a somewhat larger dose, and several are often dead at birth. As Evans and Burr proved, the rat unit ma.y be given in a single dose, repeated doses being unnecessary. Description of Rat Tests-Four rats were ordinarily used in each test, but the only significant rats were regarded as those showing the erythrocyte or implantation sign mentioned above. The re-