THE ANATOMICAL RELATIONSHIPS OF THE HYPOPHYSIAL STEM AND THE MEDIAN EMINENCE1

Abstract

RCENT physiological observations, such as those by Magoun, Fisher and Ranson(1) have made desirable an accurate definition of the line of junction of the neurohypophysis and the hypothalamus. Unfortunately no one has endeavored to determine this line of junction on the basis of the cytologic charac teristics of these areas. In view of the fact that their microscopic structure is in each instance typical and vastly different fromthe other and that the neurohypophyais contains a cell, the pituicyte, peculiar to it, this is surprising. True, efforts at delineation of this junction on the basis of the relative vascularity of tlie two tissues or of their susceptibility to staining with vital dyes (a) have been made; while Tilney (3), Magoun and Ranson (4), and Gersh (5) have declared the median eminence, formerly regarded as part of the hypothalamus, to be composed of neurohypophysial tissue.