Further experiments on the antirachitic action of yolk of egg.

Abstract

In previous communications 1 it was shown that egg yolk is able to confer protection or bring about cure in rickets, both in infants and in rats. Further experiments have shown that as little as one drop (0.05 gm.) a day (fed by pipette) is sufficient to protect rats which are on a ration markedly deficient in phosphorus. It is of much less protective value when the rats are given a rickets-producing dietary very low in calcium. Boiling the egg for twenty minutes does not appreciably diminish the potency of the yolk in relation to rickets. Drying the yolk and keeping it in a dried state markedly reduces its antirachitic value. When 0.05 gm. was given subcutaneously, the yolk did not confer protection, but this was accomplished by injections of 0.15 gm.

Various fractions of egg yolk were tested in protective experiments on rats receiving the low phosphorus diet. It was found that the non-saponifiable fraction was protective and a preparation was obtained about 90 times as concentrated as the original yolk. It is, however, possible that its potency is not restricted entirely to this fraction.