y 



112 MENTAL EVOLUTION IN ANIMALS. 



lent work on the " Diseases of Memory," wliicli has now 

 been translated, and forms a member of the International 

 Scientific Series. In this work M. Eibot deals fully Avith the 

 complete analogy that obtains on the objective side between 

 ganglionic memory — or, as he calls it, organic memory — and 

 the physical changes in the cerebral hemispheres which are 

 (concerned in true or conscious memory. I should like to 

 express my satisfaction at finding so singularly close a corre- 

 spondence between the views of M. Eibot and myself upon 

 these matters, which extends into so many details that I have 

 left my chapter already referred to verbatim as it was origi- 

 nally written ; for it speaks in favour of the truth of one's 

 results when they have been independently arrived at by 

 another worker in the same field.* 



And here I may observe that I also agree with M. Eibot 

 in his view that the phenomena of memory, whether 

 " organic '"' or " psychological," present no point of true 

 analogy with any such purely physical phenomena as the 

 permanent effects upon a photographic plate of a short 

 exposure to light, or any other phenomena where living 

 organisms are not concerned. I further agree with him in 

 his view that the earliest analogy we can find to memory is 

 to be sought in living tissues other than nervous, and that it 

 occurs in protoplasm. Thus he quotes Hering to the effect that 

 muscular fibre " becomes stronger in proportion to its use." 

 To this it may, I think, be objected that there is no evidence 

 of individual muscular fibres thus gaining in strength by 

 use. I think a better, because a more unexceptionable, parallel 

 is afforded by the fact that when a constant galvanic current 

 is allowed to pass for a short time through a bundle of mus- 

 cular fibres, in the direction of their length, and is then opened, 

 a change is found to have been produced in the excitability 

 of the fibres such that they are less excitable than before to 

 a stimulus supplied by again passing the current in the 

 same direction, and more excitable to the stimulus sup- 

 plied by passing the current in the opposite direction. This 

 memory of a muscle touching the direction in which a gal- 

 vanic stimulus has passed endures for a minute or two after 

 the current has ceased to pass (Frog). I have found this 



* Any one who cares to trace the correspondence may do so by comparing 

 my chapter above alluded to with the first chapter of M. Eibot's work. 



