Psycho-mnemonic Phenomena 321 
greater or less number of specific or mnemonic potential 
elements differing from one cell to another. But we 
must bear in mind that this differentiation is not acquired 
exclusively after birth, but appears already within cer- 
tain limits, at least in relation to all the congenital 
instincts, during ontogeny. 
“We see,” writes Hering, “how an entire group of 
sensations become reproduced with such vividness and 
in such precise order of space and time that it can 
deceive us as to its reality. This shows us in a most 
striking way that even after the sensation and percep- 
tion in question has long since disappeared, there remains 
still in our nervous system a material trace, an alteration 
of the molecular or atomic connections by which the 
nervous substance is rendered capable of reproducing 
these physical processes, with which the corresponding 
psychic process of sensation and perception is also deter- 
mined.”—“The representations do not last as representa- 
tions but what does persist is that particular attunement 
of the nervous substance, by virtue of which when it 
is properly struck it sounds again today the same note 
which it gave forth yesterday.” 2% 
This conception of Hering of the disposition of the 
nervous substance to sound again the tone of yesterday 
is derived from the physical phenomenon of acoustic 
resonators. The nervous substance which would be made 
to vibrate in a given specific way at a given point by a 
definite elementary sensation or representation would re- 
main from that moment capable of vibrating always and 
exclusively according to that specific mode. According 
to the hypothesis of mnemonic elements on the contrary, 
2%5Hering: Uber das Gediachtnis etc. P. 8, 9. 
