Address to the American Neurological Association / by S. Wier [i.e. Weir] Mitchell.

  • Mitchell, S. Weir (Silas Weir), 1829-1914.
Date:
1909
Catalogue details

Licence: In copyright

Credit: Address to the American Neurological Association / by S. Wier [i.e. Weir] Mitchell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    to allow us-to go beyond this statement, viz., the temperature coefficient of the nerve impulse indicates that chemical reactions are involved in the propagation of impulse. In which way they are involved we cannot exactly state at present; we only know that the salts, especially the ratio between the concentration of the sodium ions and the concentration of the calcium ions in the nerve, play an important role in this sense, that within certain limits an increase in this ratio causes an increase in irritability of the nerve, and a decrease has the reverse effect. It also seems pretty certain that oxidations are a necessary pre-requisite for the life of the nerve, and possibly also for the propagation of the nerve im- pulse. Rather,” he adds, “ than make hypotheses at this stage, I feel, with Professor Ernst Mach, that scientists must learn to endure an incomplete world-view. Our hypotheses mainly serve as an attempt at escaping an enforced condition of intellectual slavery.” Considering the tentative views held by Loeb and others and the present laboratory indecisions, you will see how far we are from the practical helpfulness which as neurologists we should anticipate if the nerve impulse could be proved to depend on minute and essential saline interchanges, I am personally of opinion that this research should recommence with fresh studies of that form of excito-contractile impulses which is found in plants and is probably identical with that observed in animals. The resemblance is so striking as to have over and oVer caused the assertion of identity of the phenomena of transmission to be made by botanists. If they are right, it must, I think, follow that whatever explains transfer of excitatory energy in the one king- dom must equally explain it in the other. But while this question in animal life has been variously approached, in the vegetable kingdom the possibility of chemical explanation has been as yet very little considered. As I, who am not a botanist, am talking to men probably unfamiliar with vegetable physiolog>q I may be pardoned if, with brevity, I try to arouse in you concerning these two correlated physiologies the interest they have awakened in me. For perhaps individual reasons many men have some curious sense of mysterious relation to the outer world of trees and flowers; but he who has watched the mimosa, in its most sen- sitive condition, make its quick responses, or as if its mood had