“7th. On the basis of the hypothesis above mentioned we have shown that the law of Weber-Fechner admits of a rational physico-chemical interpretation, and that the result thus obtained, provided the hypothesis above mentioned be an exact representation of facts, is that the intensity of the sensation is at each instant proportionate to the mass of the product of the autocatalyzed chemical reaction above mentioned and, consequently, to the extent of the trace of memory.” While it is easy to understand that auto-catalysis may take part in the chemical process which underlies the performance of simple volition, as inferred by Robertson,[60] and perhaps reproduction in the memory process, it is difficult to understand how such a chemical action can explain conservation. The problem is not that of acceleration of an action, but of something like the storing up of energy. Rignano[61] has proposed an hypothesis according to which the cells of the nervous system are to be considered as so many accumulators, analogous to electric accumulators or storage batteries. “The similarities and differences which nerve currents present in comparison with electric currents warrant us in assuming in nerve currents some of the properties of electric currents, and in attributing at the same time to the first other properties which the electric do not possess, provided these qualities are not incompatible with the others.” Now, according to the hypothesis, the specific nervous current set up by any stimulus forms and deposits in the nucleus of the cells (through which the current flows) a _substance_ which adds itself to the others already there without changing them and which is capable, under appropriate conditions, of being discharged and restoring the same _specific_ current by which it was produced. Each cell thus becomes what Rignano calls an _elementary nervous accumulator_. He points out that “both the conception of _accumulators of nervous energy in tension_, and that of _accumulators of a specific nervous energy constituting their specific irritability_,” which the hypothesis includes, are not new but “an ordinary conception very generally employed.”... “The only new thing which the above definition includes is the hypothesis that the substance, which is thus capable of giving as a discharge a given nervous current, _was produced and deposited_ only by a nervous current of the same specificity, but in the inverse direction, and could have been produced and deposited only by such a current.” "In just this capacity of restoring again the same specificity of nervous current as that by which each element had been deposited one would look for the cause of the mnemonic faculty, in the widest sense, which all living matter possesses. And further the very essence of the mnemonic faculty would consist entirely in this restitution.“