THE SYMPATHETIC SYSTEM OF NERVES. 549 



point where it enters the cell. But I have also satisfied myself 

 that very frequently, besides the relatively thick processes that 

 originate in the cell substance itself, a second system of very 

 fine filaments is given off, that take their origin from the 

 nucleus and nucleolus. These fine processes are nothing else 

 than the already mentioned nuclear and nucleolar filaments. 

 They run in part in the track of the coarse processes, and in part 

 pursue their own path ; it very seldom happens, however, that 

 these fine fibres can be traced for any considerable distance 

 after their emergence from the cell substance. On one occasion 

 I observed a fine process of the kind just described become 

 continuous with the axis-cylinder of a medullated fibre ; and 

 Beale has made a similar observation. The origin of the 

 straight fibre from the nucleolus, which is now and then observ- 

 able, cannot certainly be regarded as the rule. In fig. 267 a cell 

 from the sympathetic of the Frog is depicted, where the 

 straight process, in which with high powers a fibrillar structure 

 may be established, penetrates through the cell substance to 

 the nucleus. After having been traced to this body, however, 

 its precise mode of ending escapes observation. Nevertheless, 

 I do not doubt but that, under favourable circumstances, the 

 straight fibre could in some cases be shown to be directly con- 

 tinuous with the nucleolus. 



Fig. 267. 



Fig. 267. Exhibiting the nerve process extending as far as to the nucleus. 



Further, the various authors are not agreed upon the point 

 of origin of the spiral fibre. Arnold has stated that it develops 

 from a plexus formed by the nucleolar filaments in the sub- 

 stance of the cell. Beale considers that it proceeds from the 

 more superficial portion of the cell substance, where a few 

 accessory nuclei usually lie. The view of Arnold received in 

 the first instance the most complete corroboration by Cour- 

 voisier, but in a later publication he has admitted it with some 



