From various sources in recent years new facts have been unearthed both in clinic and laboratory which have thrown light on many heretofore Obscure activities Of the pituitary gland. As the archaeologist is enabled to construct an historical background through the fortunate discovery Of a few telling fragments, so may the physiologist venture to build up at least a provisional working hypothesis on the basis Of a few suggestive findings. Needless to say, in either case such a background can at first be but roughly indicated. As is true Of the painter's canvas, preliminary studies must be made, patiently worked over, and altered from time to time, possibly even in their fundamental arrangement, if the superimposed details are ulti mately to furnish a satisfying sense Of proportion.