Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

masked by a crowd of circumstances that arise in electro-thera- peutics. But if we set out with the idea, laid down in the out- set by Faraday, that the electric current, which acts in electrol- ysis, is only the chemical, transported, or put into process of transportation from one particle or point to another, under the form of a current acting at a distance instead of acting only at the contact, then the law of electro-chemical equivalents is a necessary and rigorous consequence of this; for the same chemi- cal force must decompose every where an equivalent of the com- pound body. We may, therefore, conclude that the law of electro-chemical equivalents is found to be justified within the limits of error of observation, and that if there is a portion of electricity that traverses the liquid without producing appreciable decomposi- tion, it can be only a very small fraction of the total quan- tity of electricity transmitted. But if the liquid acted upon is in living tissues, then this effect is somewhat modified, provided, also, the current is moderate, for there may not be so much elec- trolysis as catalysis; i. e., there is doubtless here more of the work of composition than of decomposition. The influence that naturally determines sensation and mus- cular contraction in the normal state, is now termed the " ner- vous force" Formerly this was termed the nervous fluid; but this arose from an hypothesis, which, in truth, has nothing to jus- tify it; but the will or volition is, before and above all, the great moving cause that in the normal state is capable of developing in nerves the nervous force, which transmits, or rather propagates, itself to the muscle, producing in them contraction and motion. Next to the controlling power of the will over the motor nerves is the action of electricity ; then mechanical action, chemical action, heat and cold. But in its mode of action, electricity differs from all the other exterior agents in characteristics that are alone and peculiar to itself. Its great relative importance here is seen by its effects approximating so nearly to those which the will calls into action, and which natural effects we believe we are able to restore again to the dominion of the will, under certain circumstances, even when it has been in effect ap- parently totally lost.