A STUDY OF THE LOCALIZATION AND DISTRIBUTION OF GLYCOGEN IN EARLY STAGES OF THE CHICK EMBRYO

Abstract

The localization and distribution of glycogen in the germ layers of chick embryos at stages 4, 5, and 6 (Lillie and Hamilton, 1952) was studied by means of the periodic acid – Schiff reagent as used by McManus (1948). In general the glycogen content of the embryos is greatest in the definitive streak stage, less in the head process stage, and least in the head fold stage. Glycogen is abundant in the ectoderm of embryos at stage 4, with a moderate decrease in stages 5 and 6. Glycogen is scarce or almost absent in the mesoderm and endoderm at all stages. There is a definite relationship between the amounts and distribution of glycogen and early developmental processes.