THE RELATION BETWEEN REFRACTORY PHASE AND ELECTRICAL CHANGE

The object of this communication is to bring forward evidence in favour of an intimate association between the absolutely refractory phase of a tissue and its negative electrical variation, and between the relatively refractory phase and the positive return electrical change. A general argument in favour of the association is the fact that the absolutely refractory phase corresponds in all probability with a katabolic or disintegrative change, while the relatively refractory phase certainly corresponds with an anabolic or reintegrative change. On the other hand, the negative change of potential accompanying activity is uniformly assumed to be katabolic, the positive return change to be anabolic. In addition to this, experiment has shown that the time of the refractory phase as a whole closely corresponds with the time of the complete electrical change. Specific experimental evidence in favour of the association is furnished by a comparison of Waller's experiments on protoveratrinised nerve with Tait and Gunn's and Tait's experiments on yohimbinised nerve. (From a pharmacological point of view, protoveratrine is virtually identical with yohimbine.) Protoveratrine greatly modifies the character of the electrical response of nerve, yohimbine greatly modifies the refractory phase; and these modifications are such as are not known to be produced by any other agent. Analysis has in each case shown that the modification consists of an enormous prolongation of stage II.—relatively refractory phase or positive return electrical change, as the case may be—without any corresponding modification of stage I., i.e. of the absolutely refractory phase, or of the original negative electrical change. The available data do not, however, allow of an exact correlation of the time‐duration of the individual events.