GLYCOGEN IN THE NERVOUS SYSTEM 453 
chemists it was pointed out by them that where large amounts 
of glycogen might be present in some elements of the organ or 
animal, the amount of glycogen relative to the entire bulk might 
be so small that it would be wholly missed by the usual chemical 
analyses. It is also now recognized that chemical analyses by 
the aid of the microscope have as great validity as those made in 
the usual way, where relatively large amounts of substance and 
reagents must be used (Chamot, 715). Furthermore, the micro- 
scopical method is the only one by which the exact anatomical 
location of the glycogen can be determined. For the precise 
steps employed in fixing, imbedding, sectioning, and staining 
and mounting tissues for glycogen, see the note at the end of this 
paper. It may be stated here that to make sure that the ma- 
hogany red substance shown in the nerve cells is glycogen, the 
test was made in every case with saliva, which transforms gly- 
cogen to sugar and therefore renders it no longer stainable with 
iodin; it is believed therefore that the results here given, and 
which were obtained over and over on many different specimens, 
can be relied upon. 
GLYCOGEN IN THE NERVOUS SYSTEM OF AMPHIOXUS AND ASYM- 
METRON FROM BERMUDA AND AMPHIOXUS FROM NAPLES 
In 1904 while a member of the group of workers at the Ber- 
muda Biological Station, under the direction of Dr. E. L. Mark, 
advantage was taken of the abundant Amphioxus material there 
available to investigate the tissues for glycogen. It was found 
rather generally distributed but not in striking amounts except 
in the most unexpected situation, viz., in the large nerve cells of 
the central nervous system. This was so opposed to the findings 
of all previous investigators of glycogen in the nervous system 
that it was only after repeated verifications on specimens of 
various sizes that it was accepted. While any nerve cell appar- 
ently might contain glycogen, this substance was most strikingly 
shown in the large nerve cells associated with pigment. Whether 
or not there is any connection, it is a rather striking fact that 
glycogen in large amount is found in the retinal nerve cells of 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 27, No. 4 
