NERVE TISSUE 



143 



According to the continuity theory, while the perifibrillar substance is inter- 

 rupted as above described, the neurofibrils, are continuous. According to 

 this theory the neurofibrils, which form a plexus or network, within the cell 

 body and dendrites, are connected with a pericellular network — the Golgi net 

 — which closely invests the cell body and its dendrites. Externally the Golgi 

 net is further connected wiih the neurofibrils of the axoncs and collaterals 

 of other nerve cells. This connection is either direct, or, as some believe, through 

 another general (diffuse) extracellular network. The neurofibrils are thus, accord- 



FiG. 87. — .4, B, C, Three cells of the Ventral Cochlear Nucleus of Rabbit, showing 

 terminals of fibres of the cochlear nerve and their relations to the cell bodies (Cajal). 

 a, a, a, Fibres of the cochlear nerve, which break up into terminal arborizations upon the 

 cells; h, c, terminal rings. The points of contact between the terminals of the axone of 

 one neurone and the cell body and dendrites of the other neurone constitute a " synapsis." 



ing to this theor>', continuous and form two or possibly three continuous net- 

 works: {a) an intracellular network, {b) a pericellular network (Golgi), and (c) 

 a more diffuse extracellular network, lying between the cells. The existence of 

 (c) is extremely doubtful and it seems probable that the Golgi network is either 

 non-nervous or an artefact. Thus the main point at issue is whether the 

 neurofibrils, in such, pericellular terminals as are illustrated in Fig. 87, are con- 

 tinuous with the neurofibrils within the cell enveloped or are separate from the 

 latter. 



The individuality of the neurone and the interdependence of its various parts 

 are strikingly shown by its behavior when injured. That degenerative changes, 

 which progress to complete disappearance of the nerve structures, take place in 



