On Memory and the Specific Energies of the Nervous System

From the PUBLISHERS' PREFACE. Dr. Ewald Hering, professor of psychology at the University of Leipsic, is not a voluminous writer, but he has done considerable work in investigating the nature of specific colorsensations and the processes of life. The results of his studies have largely been accepted by his colleagues and his little essay "On Memory" which contains a popular exposition of this fundamental problem has become classical. Concerning its significance for physiology, Prof Michael Foster of the University of Cambridge says in the Encyclopedia Britannica, Vol. XIX, page 22: "If the ingenious speculations of Hering, that specific colorsensations are due to the relation of assimilation (anabolism) to dissimilation (katabolism) of protoplasmic visual substances in the retina or in the brain, should finally pass from the condition of speculation to that of demonstrated truth, we should be brought face to face with the fact that the mere act of building up or the mere act of breaking down affects the condition of protoplasm in other ways than the one which we have hitherto considered, viz., that the building up provides energy to be set free and the breaking down lets the energy forth. In Hering's conception the mere condition of the protoplasm, whether it is largely built up or largely broken down, produces effects which result in a particular state of consciousness. Now, whatever views we may take of consciousness, we must suppose that an affection of consciousness is dependent on a change in some material. But in the case of color-sensations that material cannot be the visual substance itself, but some other substance. That is to say, according to Hering's views, the mere condition of the visual substance as distinct from a change in that condition determines the changes in the other substance which is the basis of consciousness. So that, if Hering's conception be a true one (and the arguments in favor of it, if not wholly conclusive are at least serious), we are led to entertain the idea that, in addition to the rough propagation of explosive decompositions, there are continually passing from protoplasm to protoplasm delicate touches compared with which the nervous impulses which with such difficulty the galvanometer makes known to us are gross and coarse shocks. And it is at least possible, if not probable (indeed present investigations seem rapidly tending in this direction) that an extension of Hering"s view, with such modifications as future inquiry may render necessary, to other processes than visual sensations, more especially to the inner working of the central nervous system, may not only carry us a long way on towards understanding inhibition and spontaneous activity but may lay the foundation of a new molecular physiology. This however is speculative and dangerous ground, but it seemed desirable to touch upon it since it illustrates a possible or probable new departure. What we have said of it and of the more manageable molecular problems of physiology will perhaps show that, vast and intricate as is the maze before the physiologist of to-day, he has in his hand a clue which promises, at least, to lead him far on through it..."..