Rensselaer Republican, Volume 16, Number 14, Rensselaer, Jasper County, 13 December 1883 — ANIMAL ELECTRICITY. [ARTICLE]

ANIMAL ELECTRICITY.

A Heart Living by Itself—Electricity in the Eyes and Arms—The Charlatan's Opportunity* In Dr. Kendrick’s lecture before the British association it was shown, by projecting its image on a screen, that the uninjured frog’s heart, isolated from the body, still lives, and while beating gave with each beat an electrical variation, as shown by the swing cf the galvanometer needle. The uninjured heart gives no current, but when slightly injured there is a variation in iw electrical state with each beat. Then the lecturer showed that light causes an electrical change in the eye. Placing the eye of a frog in the galvanometer cushions,jitfcvas shown that there was a current passing from the corner to the back of the eye. In the dark little or no change could be seen except what might be due to the drying of the living structures forming the eye; on allowing light to fall on the eye, there was at once an increase in the current. This continued for a time, then began to fall off, and on light being reihoved there was another increase, and then a sudden and rapid falling off. The action, first shown by Prof. Holmgren, Prof. Dewar and the lecturer, showed a specific influence of light on the retina. It could not be called a negativevariation. —It 4ndieated~ chemical changes occurring in the retina. Lastly, the lecturer showed the production of currents from the living man. Placing the hands in two vulcanite troughs communicating by platinum plates with the galvanometer, and filled with a weak solution of salt he showed that on contracting one arm a deflection of the galvanometer needle was produced. When both arms were quiet there was no current; on contracting one arm a current was at once produced. This current, the lecturer was inclined to think, was due to action of the fluid on the skin and not to currents from the muscles, and that the differences were due to differences of contact-- In summing up, after a few remarks regarding electric fishes, the lecturer said that all of these electrical changes were really expressions of vital changes occurring in living tissues under the action of stimuli. It was no part of the functions' of nerves, muscles or of the retina of the eye to produce currents under the action of their relative stimuli, but such currents indicated chemical changes in the organs or tissues. For example, the contraction of a muscle is a movement following or consequent upon many chemical changes, among the results of which were the production of heat and differences of electrical potential. Thus, there was no special production of electricity except in the case of electrical fishes, and possibly of some other animals. Iti most animals, including man, the production of currents was an incidental phenomenon, indicating chemical operations and nothing more. Besides, the currents so produced were feeble and evanescent, and bore no relation to the general well-being. Consequently an attempt to influence the living body bymagnets had no rational basis. The lecturer had tested this question by powerful electro-magnets and had not been able to detect that they had the slightest" influence on any vital phenomena. It need hardly be added that the so-called phenomena of animal magnetism are of an entirely different /kind from those discussed. They are of a subjective character dependent upon peculiar states of the nervous system, haying nothing whatever to do with electricity or magnetism; but still, in a sense, they are a phenomena as real as those of physical science. Their subjective character, however, renders them specially difficult of investigation, and consequently they are more liable to fall into the hands of the charlatan. One safeguard against this is the recognition of what the electrical phenomena of the living body really mean, and one purpose of this lecture will be served if it shows that to detect and account for these phenomena requires the most refined methods of the physicist and of the physiologist, and that they give us only a glimpse into the intricate changes occurring in living tissue.—London Times.