Abstract
Adrenaline added to hanging-drop cultures of embryonic chick liver had no effect on their glycogen content. Yet in the intact embryo adrenaline produced a marked reduction in liver glycogen. Anaerobiosis caused the complete breakdown of glycogen in a large no. of cultures. In the intact embryo muscle glycogen was not reduced by adrenaline until about the 18th day of development, which result is in agreement with the findings of Needham et al. that the enzyme system, upon which adrenaline might act, was not present in the early stages of development.