CELLS AND FIBRES. 373 



ence,* it is allowable to assume a corresponding difference in 

 function ; but with regard to the molluscs here referred to 

 (namely, the genera Doris, Flem'obranchus, Aplysia, Solen, 

 and Limax), this structural difference does not exist : the 

 nerve is but a continuation of the ganglion, the whole form- 

 ing one tube, through which, by a little pressure, the con- 

 tents of the ganglion may be pressed out of the cut end of 

 the nerve. If only one example of such an arrangement 

 could be found, it would suffice to unsettle the whole theory 

 of nervous action, as at present understood. The battery 

 and wire can therefore no longer serve as a comptarison ; and 

 the theory of conduction needs revision. 



It may readily be imagined that the doubt thus raised, left 

 me no peace. I dreamt of ganglia and their prolongations. 

 They visited me in sleep, in half sleep, in noontide walking, 

 and in evening reveries. Por weeks I was in a " nervous 

 fever." Every animal I could lay hands on was sacrificed to 

 the inexorable scalpel, — from the new-born Puppy, to the 

 Bee which flew into my study ; from the Lizard, Frog, and 

 Toad, to the Grasshopper and Locust ; from the hideous 

 Dogfish, to the graceful Pipefish ; from the Hermit crab, to 

 the Dragon-fly larva ; from the garden Snail, to the Slug ; 

 from the Solen, to the Sea-hare. Scores of dissections only 

 increased my doubts respecting current doctrines ; since, 

 whether fresh specimens, or j^reparations after treatment with 

 alcohol, with chromic acid, and with acetic acid, were under 



* If Stilling' s recent investigations should prove correct, nothing but slight 

 moi-phological differences exist between nerve-cells and nerve-fibres. See his 

 work previously referred to. 



