40 LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



The nerve-substance proper which fills out the spaces in the 

 above-described net-work consists of ganglion-cells and nerve- 

 fibres. 



The form of the ganglion-cells is extremely varied. Round- 

 ish, almost spherical bodies of small size are seen, together with 

 multipolar cells with many processes, and twenty times the size 

 of the smaller cells. 



FIG. 23. 



From a piece of spinal cord. A and S, ganglion-cells ; at Z, axis-cylinder; p, protoplasmic 

 process ; c, neuroglia-cells. (After Raiivier.') 



In the lobus nervi vagi of the torpedo and in the medulla 

 oblongata of the river lamprey are found such enormous ganglion- 

 cells that they can readily be seen with the naked eye. In the 

 spinal cord of the electric eel, the malaterus, are two isolated 

 ganglion-cells of such a size that the huge single nerve-fibre 

 which each gives off is sufficient to supply the very large elec- 

 tric organ of the animal. 



