Abstract
In previous work it has been shown that the apical ends of isolated stem of Obelia colonies are electropositive (galvanometer circuit) to middle or basal regions of the same stem. 1 These differences of electric potential are maintained and therefore a continuous output of electrical energy occurs under normal conditions of life in sea water. The processes upon which this output of energy depends can be inhibited in a perfectly reversible manner by cyanide, ether and chloroform.
Tissues of the stem, the electric potentials of which have been repeatedly and reversibly decreased, retain their normal capacity for growth and regeneration and also their normal sequence when removed to pure sea water.
The normal electrical polarity of the stem as a whole is a result of the inequality of the P.D.s across the ecto-endoderm of the apical (young) and basal (old) ends of the stem. The ecto-endoderm of the apical end is usually the seat of the highest P.D. From this it follows that removal or reversal by means of cyanide, ether and chloroform, of the electrical polarity of the stem as a whole does not necessarily involve a reversal of the direction of the P.D. across the ecto-endoderm but merely an unequal decrease in its P.D. at apical and basal ends.
Alcock 2 and recently Csillag 3 have shown that the P.D. in the frog's skin can be reversibly decreased with suitable concentrations of ether and chloroform applied to both sides of the skin. Experiments by the writer show that cyanide also decreases reversibly this P.D. But in no case has a reversal in the direction of P.D. across the skin been obtained.
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