ANATOMICAL AND ELECTRICAL EXAMINATION. 277 



brought into contact with an active voltaic circle, participate Analofr with 

 in all its qualities, physiological and chemical, give shocks, the secondary 

 produce decompositions, and continue to do so for a time aft- plles of Rltter - 

 er the original influence has ceased, so a similar conservation occurs in the 

 interior of the vesicle ; and this I consider to "be the consequence of the 

 difference of structure of the fibrous axis cylinder and the granular vesi- 

 cle contents. The continuous lines along which the influence has been 

 coming terminate on reaching the vesicle, and are replaced by a divided 

 and inferior conveying structure, a structure which recalls at once the sec- 

 ondary piles of Hitter just alluded to. 



We may therefore truly say that these electrical experiments offer a 

 striking confirmation of the truth of the conclusions to Coincidence of 

 which we have come from the study of the anatomical struc- anelectrical 

 ture of a nervous arc. They assure us that a vesicle, and examination, 

 therefore a ganglion, has a double office to perform, the stopping, reserv- 

 ing, storing up a part of the influence which is brought to it, and also 

 the conveying of that incident influence into many new channels. These 

 conclusions are altogether independent of any conception of the nature of 

 the nervous agent : it may be identical with, or allied to, electricity, or it 

 may be a totally different principle. It is not that question which we 

 are concerning ourselves with now. We are dealing with structure and 

 its interpretation. Whatever our views may be of the nature of inner va- 

 tion, we shall find ourselves constrained to infer that the delays, diver- 

 gences, detentions, and subsequent surrender, the opportunity of diverg- 

 ing from one into many new channels, or conversely the convergence fro in 

 many lines of entry into a single one of exit, with all the accompanying 

 interferences and reactions, must be common to both the electrical and 

 the nervous agent, for they depend, not upon the qualities of those prin- 

 ciples, but upon the anatomical structure through which they are passing. 

 With these remarks I proceed to an exposition of the typical construc- 

 tion of the nervous system, pointing out its successive com- Hypothetical 

 plications. The hypothetical diagrams which I shall now SS2^2*2 

 present are chiefly for the sake of impressing the conclu- anism. 

 sions at which we have arrived from a consideration of the structure of 

 the nervous elements, fibrous and vesicular, the experimental determina- 

 tion of those functions, and their electrical phenomena. That these dia- 

 grams are, however, somewhat more than imaginary 

 sketches, will be obvious from a consideration of the 

 nervous mechanism of the articulata, which offers 

 striking illustrations of them. 



The simple automatic nerve arc, Fig. 122, consists 

 of an afferent or centripetal fibre, #, connected contin- 

 uously with an efferent or centrifugal fibre, e. An 



