PINEAL AND METAMORPHOSIS THE INFLUENCE OF PINEAL FEEDING UPON THE RATE OF METAMORPHOSIS IN FROGS

Abstract

Pineal hastens the rate of metamorphosis in much the same manner as thyroid does, but is not so powerful. If the feeding of the pineal is discontinued, development slows up. Resumption of pineal feeding results in a sudden speeding up of the metamorphosis. Unlike the findings of McCord (1917) the pineal fed individuals lost weight rapidly while the weight of the controls remained more nearly constant. Twenty-two pineal fed individuals developed fore legs and 8 passed through the tail absorption stage into that of the adult form in course of 31 days. No change whatever in the way of differentiation was noted in the controls.