Gonad-Stimulating Potency of Individual Pituitaries

OWING to the economic importance of the egg-laying characteristic of the fowl much research has been published on the inheritance of those phenomena associated with reproduction and sexual development. However, comparatively little is known concerning the physiological processes involved in development and activity of the reproductive organs. A knowledge of these processes is essential to a thorough genetical study of the reproductive phenomena in birds. The researches reported were planned in order to obtain a method by which the bases of individual differences in gonadal function might be evaluated. It has been shown by previous workers (Allen, 1932, p. 778) that the pituitary body is chiefly responsible for the development of the immature gonad of the chicken and duckling. Jaap (1934) found that the testes of adult Mallard drakes may be caused to increase in size during the winter months by feeding desiccated thyroid. This increase is due presumably to . . .