268 VESICLES ARE MAGAZINES OF FORCE. 



adjacent ganglia ; <?, c, c t <?, branches to the viscera and spinal nerves ; d, 

 nerve-cells ; e, nerve-tubes traversing the ganglion. (Valentin.) 



For the explanation of the function of the nerve centres, it is essential- 

 Function of ly necessary that we should have clear views of the function 

 Sedanatom- ofthe nerv<3 vesicles. It has appeared to me that their duty 

 icaiiy. is manifested by their anatomical relations. The influence, 



whatever it may be, which passes along a nervous cord, is completely 

 isolated therein, and never leaves the fibril in which it is passing from 

 its origin to its termination. It is isolated by the white substance of 

 They permit Schwann. But it is very plain, as a thousand phenomena 

 esca^ 'intcT * ^ ^ ie nervous system prove, that there are places of escape 

 new channels, for this influence, although it may be confined in the nerve- 

 tube, and these places can be no other than the vesicles. Their caudate 

 aspect, or multipolar form, as it is often termed, will bear no other inter- 

 pretation. The disturbing influence, coming along the axis cylinder of a 

 nerve-tube, finds itself delivered into the granular material in the interior 

 of a vesicle, a material physically continuous, in the opinion of many 

 physiologists, with the structure of the axis cylinder. Through this 

 granular material the influence is transmitted, and if the vesicle should 

 have on its distant contour two or more nerve-tubes connected with it, 

 it would seem to be the necessary result of such a state of things that 

 the influence will pass down all those channels. For these reasons I re- 

 gard the nerve vesicles as being constructions for the purpose of 'opening 

 out the closed nerve tubules, and permitting them to deliver their energy 

 into new tracts. 



But more than this. Whatever may be the manner in which the 

 Diffusion of in- nervous influence is propagated, or conducted from point 

 granular mate! * P om * ^ tne granular material within the vesicle, there 

 rial. must be now, since there is no structure to prevent it, a lat-* 



eral spreading of effect. It is not to be supposed that the passage is 

 made in a direct line, from the terminus of the centripetal to the origin 

 ofthe centrifugal fibre, across these caudate vesicles, and restricted there- 

 to. There is no isolator to confine it in any such track, and it seems to 

 follow of necessity that the whole contents of the vesicle must be affect- 

 Vesicles retain ed, and this irrespective of its magnitude. Such a condition 

 ad r arTma'-a- ^ tnm g s introduces the suspicion of a second great duty 

 zines of force, which the vesicles may discharge in retaining within them- 

 selves, at all events for a short period, the influences that have thus es- 

 caped laterally, and thus they become temporary magazines of power. 

 Unipolar, bi- And perhaps this may be the true interpretation ofthe action 

 polar, muitipo- of unipolar and bipolar vesicles; the unipolar being a capsule 

 for the collection and conservation of the entire delivered in- 

 fluence, the bipolar to admit of the passage onward of a large portion of 



