452 SIMON H. GAGE 
In Pfliger’s book on glycogen (2nd edition, ’05, pp. 159-160) 
is the statement with reference to the nervous system of the 
adult; that Pavy (1881 had reported the presence of glycogen 
in a normal adult brain analyzed by him, and that Cramer (’80) 
had found traces in the brain of a person dead of diabetes. On 
the other hand Barfurth (’85, p. 297) and others, reporting the 
analyses for the normal adult brains of rabbits and dogs, asserted 
that no glycogen was found by them. 
Pfliiger says further on with reference to glycogen in the 
nervous system in embryos: 
Auch im Embryonalzustand ist bisher kein Glykogen in der sich 
bildenden Nervensubstanz aufgefunden worden, was bereits Claude 
Bernard untersucht. In neuester Zeit haben G. Fichera (’04) sowohl 
als E. Gierke (’05) das Nervensystem auf Glycogen untersucht und 
nur negative Ergebnisse gemeldet. 
In 1904 I was fortunate enough to discover the presence of 
glycogen in the nerve cells of the central nervous system of 
Amphioxus, and began then a systematic investigation of the 
nervous system of vertebrates, believing that in some period of 
development glycogen would be found in the nervous system of 
each form in the ascending series up to and including man. The 
following paper is a summarized statement of the results of the 
work up to the present. For the more extended study, forms were 
selected in which abundant material, in all stages of embryonic 
as well as in adult life, could be easily obtained. These forms 
are: Petromyzon to represent the available form nearest to 
Amphioxus; Amblystoma punctatum, among the amphibians; 
the chick (Gallus domesticus) among the birds; and the pig 
(Sus scrofa) among the mammals. Other forms, including human 
material, were studied whenever opportunity offered. 
In a word, it may be stated that the hopes held out by the 
discovery of glycogen in Amphioxus were abundantly fulfilled, 
for glycogen was found in large amounts in some stage of 
development in the nervous system of every form studied. 
In carrying on the investigation microchemical methods were 
used, and not the usual analyses of entire animals or organs. 
On showing microscopical specimens containing glycogen to 
