EXPERIMENTAL PHASES OF THE PINEAL PROBLEM1

Abstract

IN PREVIOUS communications (i), attention was called to the accruing retardation in the rate of growth and the acceleration in the rate of somatic differentiation of the offspring when successive generations of white rats (Wistar strain) were given daily intraperitoneal injections of i cc. of a potent pineal extract. It seemed likely that if an excess of pineal tissue or extract resulted in a retardation in the rate of growth and acceleration in the rate of development of normal rats that removal of the pineal gland from successive generations of parent rats might result in the opposite effects, i.e., acceleration in growth and retardation in development. The success attending our experiments involving thymus implants in normal animals, thymectomy, thymectomy in split test groups, replacement therapy with thymus extract and thymus implants in normal rats (2) led us to undertake a similar group of experiments on the pineal gland in successive generations of rats.