XIV Proceedings of the Association of American Anatomists 
In tracing the appearance and disappearance of glycogen in the differ- 
ent series it was found that at the earliest stages of an organ or tissue 
no glycogen is present, but in a sort of middle stage when the organ or 
tissue is taking on something of its definitive structure, glycogen is very 
abundant, and somewhat later as the organ becomes perfected the glyco- 
gen gradually disappears. For example, in the youngest pigs the glyco- 
gen is so large in quantity in the heart muscle that the organ stains al- 
most black with Gram’s iodin solution; but in the largest pig (70 mm.) 
the glycogen had partly disappeared. In the alimentary canal the glyco- 
gen passes as a kind of wave along the tube commencing at the mouth, 
esophagus and stomach, and as the villi commence to be formed, passing 
along into the small and large intestines. 
No glycogen was found in the liver of any of the pigs studied. This 
agrees with the statement of Bernard that the liver is relatively very 
late in assuming the glycogenie function. 
The presence of glycogen in the endymal cells covering the choroid 
plexuses of the brain (Creighton) was verified, but as with the other 
organs the glycogen is not present during the first stages. Late it is very 
abundant and is present in the endymal cells not only of the relatively 
free plexus, but for a considerable distance upon the ventricular brain 
surface. This endymal glycogen was found in the plexus of the lateral 
ventricles of pigs from 40 to 70 mm. It does not appear in the endymal 
cells of the 4th ventricle until the pigs are between 50 and 75 mm. in 
length. 
Contrary to the statements of Bernard, much of the ecelomic epithelium 
is very freely suplied with glycogen (pigs of 35-45 mm.) ; and contrary 
to the statement of all authors (Bernard, Barfurth, Creighton, Pfliiger 
and those to whom these authors refer), that no glycogen is present in 
the nervous system in any stage of its development in vertebrates, abun- 
dant glycogen was found in a part of the cells of the ganglia of the dorsal 
roots of the nerves. This persists up to about 15 mm. pigs. While the 
ganglion cells possess the glycogen the outgrowing nerves seem to be 
wholly free from it and appear as almost transparent spaces, but in older 
pigs 30 to 70 mm. and perhaps older, the nerves beyond and within the 
ganglion are so densely surrounded by glycogen that they stain a deep 
brown by iodin. So far as at present known, the glycogen is not in the 
fibers but in the surrounding tissue. 
Abundant glycogen was also found in the olfactory as well as the 
respiratory epithelium of the nose and its presence is very striking in the 
epithelium of the cochlear canal opposite the embryonic organ of Corti. 
Glycogen is, therefore, normally present in parts, at least, of the central 
