EFFECT OF OVER-ACTIVITY ON SYNAPSE 265 



body and nucleus of nerve cells in activity and divided the cells 

 into many stages of alteration. As I did not undertake the meas- 

 urement of the cell body and nucleus, I will not go further into 

 details of Dolley's work ; but his method of division is, as he him- 

 self admitted, an arbitrary one, and I found many cells, which can- 

 not be assigned to any of his stages. Furthermore, I am afraid 

 that in his interpretation of things, facts are linked with hypo- 

 thetical considerations which are not directly observable. I will 

 be satisfied in the present work, if I can make sure that the 

 Mauthner cell, the synapse of which is the material of this study, 

 manifests appreciable changes in fatigue. 



THE HISTOLOGICAL MANIFESTATIONS OF THE SYNAPSE IN FATIGUE 



In these experiments which consist in forced activity, although 

 it goes far beyond the physiological limit, attention was direct- 

 ed from the first, not only to the nervous constituents of the 

 synapse directly, but also and especially to the manifestations in 

 the glia tissue, which shows the changes of the functioning nerve 

 tissue in an indirect way. It was hoped that through the study 

 of the histological manifestations in fatigue some light would be 

 thrown upon the problem, concerning the function of the neurog- 

 lia cells in the state of physiological activity. I shall first de- 

 scribe the findings in the synapse of the Mauthner cell in fatigue 

 and later go over to the consideration of the significance of the 

 manifestations. 



A. Manifestations in the Pericellular Reticular Structure of the 



Synapse 



The glia reticulum of the axone cap and of the cell surface pre- 

 sented itself in fatigue in a more or less advanced stage of devia- 

 tion from its normal configuration. In the Levaditi preparations, 

 which bring out the net figure very clearly and sharply in a dark 

 brown or black color, the alteration of the net configuration is 

 most distinctly noticeable. Figures 3 and 4 of my recent pub- 

 lication (24) demonstrate the normal condition of the glia reticu- 

 lum in the Levaditi preparation. The Golgi network, which is 

 visible on the cell surface (3) as well as in the axone cap (4), 



