GLYCOGEN IN THE CHICK EMBRYO. 67 



practically all of the musculature of the body. In some places 

 it seemed to occur in the deeper layer of the skin. 



It appeared at this age also in a mass of nerve cells lying in 

 the dorsal fissure of the spinal cord in its lumbar region (Fig. 

 14). Its occurrence in these cells was also noted by Gage. 



These results are perhaps more significant in a negative than a 

 positive way. They show that in the chick the storage of glyco- 

 gen in the embryonic tissue itself is not as extensive as in other 

 forms, and that it does not become a well-developed function of 

 the embryo in its earliest stages, though glycogen does appear 

 in some of the tissue and becomes more and more abundant in 

 later stages. The embryo depends for its energy production 

 and building material upon the food of the yolk, a part of which 

 is kept on hand in the form of glycogen in the yolk-sac. 



The majority of the drawings were made with a 16 mm. 

 objective and 4x eye-piece. For those marked high power a 

 4 mm. objective, 4x eye-piece were used. All drawings were 

 made with a camera lucida. 



