142 INNERVATION. [c HAP. XXI. 



The view, which we regard as the correct one, rests entirely upon 

 the facts of anatomy already stated. These facts lead us to consider 

 the sympathetic nerve a compound nerve, consisting of gelatinous 

 fibres, which are derived from the vesicular matter of the ganglia, 

 and of tubular fibres, proceeding from the spinal cord. These fibres 

 are bound together in the same sheath, and whatever be the proper 

 function of each, they bear to each other a similar relation to that 

 which the anterior and posterior roots of spinal nerves do in the 

 compound nerve. Originating from different sources, and possessing 

 probably different endowments, they travel in company to their 

 several destinations. 



We are aware that some physiologists of high and deserved re- 

 pute altogether deny that the gelatinous fibres, which we have de- 

 scribed as entering so largely into the constitution of the sympathetic, 

 are nervous. They regard them as an early stage of fibrous or 

 areolar tissue. The following reasons appear to us quite decisive of 

 the nervous nature of these fibres. 1. They may be distinctly 

 traced to the vesicular matter of ganglia; it is immaterial to the 

 question whether they form their connexion with the sheaths or 

 with the vesicles themselves, for we are as much at liberty to regard 

 the nucleated envelope of the vesicles as a structure essentially 

 nervous as the vesicles themselves. Parts of the encephalon appear 

 to consist of little else than nuclei. 



2. Throughout the sympathetic system these fibres and the tubu- 

 lar fibres exist in the several nerves in different but determinate 

 numbers. Sometimes the two kinds are equal, sometimes ,one pre- 

 dominates over the other; sometimes the nerves consist solely of ge- 

 latinous fibres. Now if these latter performed the office of a sheath 

 or support to the others, they would always be in due proportion 

 to each other. Moreover, the gelatinous fibres would be always out- 

 side, enveloping the tubular, which is not at all uniformly the case. 



3. Nucleated fibres, very similar to the gelatinous fibres of the 

 sympathetic exist in parts where their nervous character is indu- 

 bitable, as in the olfactory filaments (p. 8), and the nerve in the axis 

 of the "Pacinian corpuscle exhibits very much the same appearance, 

 save that it is devoid of nuclei. 



Adopting this view of the compound nature of the sympathetic, 

 it is obviously impossible to regard it either as independent of the 

 cerebro- spinal centres, or wholly depending on them. It seems pro- 

 bable that it is independent of them as regards its gelatinous fibres, 

 but dependent on them as regards its tubular fibres. 



And it may be stated that the views of anatomy which we hold 



