It was concluded that the growth stimulating effect on rats exerted by mycelium of Aspergillus oryzae is not due to protein or inorganic substance, since an addition of purified casein or sodium chloride to the vitamin added basal diet described. On the other hand, the presence of a similar effective substance (s) in commercial crude casein was indicated and a combined addition of sodium choride and the mycelium caused a slight inhibition of the growth of rats.
