Seasonal cytological changes in the anterior hypophysis of the garter snake

Abstract

FOUR TEXT FIQURES AND OXYE PLATE (TWELVE FlGURES)The present study was made in an attempt to determine the normal variations exhibited throughout the year by the cells of the pars distalis of the hypophysis of the male garter snake. The relative percentages of these cells were found to be considerably different at different seasons, and certain cytological changes accompanying the quhitative fluctuations were detectable. The possible relation between tbese seasonal changes and the male reproductive cycle is briefly considered, and mill be reported in detail in the future.From the literature that has accumulated in recent years as a result, of morphological, developmental, and experimental studies on the hypophyeis, the desirability of studying normal structural changes in the gland in relation to physiological phenomena of tho organism becomes increasingly important. An understanding of such normal variations in the anterior hypophysis is felt to be of value not only as an addition to the fund of basic information on the anterior hypophysis in general, but also as a basis for understanding and evaluating experimental work already reported, and as a reference point