168 STUDIES IN ELECTRO-PHYSIOLOGY: 

 DENDRONS AND SYNAPSES 



AND THEIR PROBABLE FUNCTION 



The grey matter of the cerebellum contains a large 

 number of small nerve-cells, and one layer of large cells. 

 These are flask-shaped and are called the cells of Purkinje. 

 The neck of the flask breaks up into branches, and the axis 

 cylinder process conies off from the base of the flask. 



The whole nervous system consists of nerve-cells and 

 their branches, supported by neuroglia (epiblastic or 

 insulating material) in the central nervous system, and 

 by connective tissue (binding and more or less non- 

 conductive) in the nerves. Some of the processes of a 

 nerve-cell break up almost immediately into smaller 

 branches, ending in arborescences of fine twigs ; these 

 branches are now called dendrons. One branch becomes the 

 long axis cylinder of a nerve-fibre, but it also ultimately 

 terminates in an arborisation ; it is called the axis cylinder 

 process, or, more briefly, the axon. The term neuron is 

 applied to the complete nerve-unit, that is, the body of the 

 cell, and all its branches. The cell processes are said to 

 contain Nissl's granules, but we have it on the authority 

 of Dr. Mott that these do not exist, as such, in the living 

 cell, and probably not therefore in the living dendron 

 (seep. 190). 



Such is a brief physiological description of the dendrons 

 and the processes associated with them, and from it there 

 does not at first sight appear to be any intimate connection 

 between them and the synapses. If, however, they are 

 considered in the light of Cajal's illustration of the synaptic 

 connections of sympathetic cells from the superior cervical 

 ganglion of man, as given by Schafer (see Fig. 90), it 

 will be seen that the evidence points to the dendrons being 

 branch-circuits, the arborisations having the function of 

 condensers, or Ley den jars ; each synaptic junction or 



