Further observations on the physiological properties of the lipins of the egg yolk

Abstract

We have continued our former studies 1 which have shown that rats which have grown as far as possible on a diet of casein, dextrin and inorganic salts, can make a new growth when small amounts of the ether extract of butter or of egg is added, while they are unable to do so when lard, olive oil, lecithin or cholesterin is added instead of the ether extracts mentioned. These have since been fully confirmed by Osborne and Mendel who have obtained similar results when unsalted butter 2 or purified butter fat 3 was employed.

We have now observed that ether, or petroleum ether extract of boiled eggs possesses the same physiological property of inducing a new growth as does the extract previously described. The active principle, whose chemical nature is still unknown, is therefore resistant to heat, and is soluble in petroleum ether as well as ether. Experiments now in progress seem to indicate that the acetone extract of egg yolk possesses in some degree at least the same power to induce new growth in rats whose growth has become suspended after long feeding with diets of purified food substances.