STUDIES ON THE PITUITARY.—V. THE AVINE DEPRESSOR RESPONSE

¹ Department of Physiology, University of Edinburgh

The substance present in pituitary extracts causing a powerful depressor response in the bird is a specific property of the fresh gland substance : it does not belong to the category of capillary poisons common to extracts of many tissues, and in particular has no connection with the histamine-like substance responsible for the secondary fall in Carnivora. It appears to be associated, like the pressor (mammalian) substance, pre-eminently with the pars nervosa rather than with the pars intermedia ; and is present in the pituitary of Fishes, Amphibia, Reptiles, Birds, and Mammals. Like the oxytocic, pressor, and melanophore stimulants, it is readily soluble in water, insoluble in ethyl alcohol, stable at the boiling-point of water, and readily inactivated by trypsin and alkali.