EFFECT OF OVER-ACTIVITY ON SYNAPSE 279 



The question whether the amoeboid gha cells come from newly 

 produced glia cells or from those which were present in the 

 synapse, is very hard to answer; but the finding of many amoeboid 

 glia cells in spite of very little increase of the glia cells may in- 

 dicate that at least some of the old glia cells give rise to amoeboid 

 glia cells. As far as the transition of one kind of catabolism prod- 

 uct into another within the protoplasm of the amoeboid glia 

 cells is concerned, I cannot add much to the description of Alz- 

 heimer (1). The fact that we find the amoeboid glia cells with 

 different granules and lipoid substance relatively more numerous 

 around the blood-vessels than the other parts indicates that the 

 catabolism products are assimilated into different granules by the 

 amoeboid glia cells and carried to the blood-vessels and de- 

 posited in the cells of blood-vessels as fat and later are gradually 

 disposed of. 



In my experiments I could not find a single case in which the 

 picture of the 'neuronophagia' of the Mauthner cell was observed; 

 this might be interpreted to mean that the alteration of the cell 

 body did not go so far in over-activity. Dolley (8) described 

 cell death as the effect of over-activity; it is rather strange to 

 me that no attention was directed to the changes of the glia cells 

 in his article. 



SUMMARY 



Careful investigation of the cell body as well as the synapse of 

 the fatigued Mauthner cell in Ameiurus revealed a nmnber of in- 

 teresting findings, which can be summarized as follows: 



1. The cell body was found either swollen or shrunken; the 

 turgescence was regarded as the result of over-activity and the 

 shrinkage as that of exhaustion. 



2. The Nissl substance was in a more or less advanced stage 

 of chromatolysis and thereby the cytoplasm was stained vari- 

 ously deeply. On the border of the nucleus a mass of stainable 

 substance was observed as the restitution phenomenon of the 

 Nissl bodies on the side of the nucleus. It was also accepted 

 that a mutual interchange of substance occurs between nucleus 

 and protoplasm in activity. 



