In three recent publications, Zondek and his collaborators1report that they have demonstrated the presence of a new pituitary hormone—Intermedin. According to them, this hormone is secreted by the pars intermedia of the pituitary gland. They further state that it differs in its reactions to chemical and physical agents and, above all, in its biologic effects from the prolans of the anterior pituitary lobe and the oxytocic and the pressor principle of the posterior lobe. In warm-blooded animals, Zondek and his collaborators demonstrated Intermedin to be present in the entire pituitary gland, in the infundibular stalk and in the walls of the third ventricle. They were unable to demonstrate its presence in any other part of the brain, or in any other tissues or fluids of the body. Zondek and collaborators state that no specific biologic effects of this hormone have been observed in warm-blooded animals. It is without