FINER STRUCTURE OF SYNAPSE 135 



strength of his study by means of his method, Bethe came to the 

 conclusion that the neurofibrils pass generally through the cell- 

 body without any net-formation. With regard to this, how- 

 ever, the cells of the Ammon's horn and the Purkinje's cell re- 

 mained uncertain to him. As far as the cells of the spinal gan- 

 glia and of the lobus electricus of Torpedo are concerned, he was 

 quite sure that there exists a net-work in them. According to 

 Bielschowsky, who worked with his method, the neurofibril 

 structure corresponds in essential features to that of Bethe. 

 Economo also demonstrated neurofibrils which do not anasto- 

 mose with the other fibrils. Like Bethe, he found also fibrils 

 which run isolated from one branch of one dendrite to another and 

 are not continuous with those in the cell-body. 



As figure 1 shows, the neurofibrils run straight or winding, 

 but smoothly through the cell-body and, generally speaking, par- 

 allel to the axis of Mauthner's cell, without any anastomoses for 

 a long distance. Some of the neurobrils can even be followed 

 through the whole length of Mauthner's cell, without any bifur- 

 cation of neurofibrils. The latter occurs, after all, only now and 

 then, and this strongly suggests that the neurofibrils do not 

 form a real mesh-work in the cell. On this point I certainly 

 agree with Bethe (6), who argued that bifurcation would appear 

 oftener, if there were really a net-w^ork in the cells. Economo 

 (15) suggested that there probably occurred merely a sticking 

 together of neurofibrils, which lie side by side in the cells. In the 

 neighborhood of the nucleus the course of the fibrils is slightly 

 more irregular, but I could not observe any anastomosis between 

 the neurofibrils. At the starting point of the cell processes the 

 fibrils radiate forth into the cell-body and at this point certainly 

 nothing of a net structure or even of a branching of single fibrils 

 could be noticed, which, with Economo (15), we would here ex- 

 pect in a real net-structure. From the processes and from the 

 interior of the cell the neurofibrils stream into the axone hillock, 

 and they could be followed pretty far into the latter. All these 

 findings speak no doubt against the existence of a neurofibril 

 net-work in Mauthner's cell. 



