This work was undertaken with the hope of determining the origin of the pressor substance in the hypophysis and its mode of secretion, and of reconciling, if possible, the divergent views concerning the depressor substance in the anterior lobe.
The ox hypophysis was used in making the extracts because the pars intermedia is sharply demarcated from the pars nervosa and can be cut away from the latter without taking nervous tissue with it (Fig. 1). In preparing the extracts an attempt was made to isolate the different portions of the gland in as pure a condition as possible. The anterior and posterior lobes were separated in the usual way by inserting scissor points in the depression anteriorly which indicates the position of the hypophysial cleft and by then cutting along the margins of the cleft until the separation was completed. The cleft is frequently filled with a rather