1. A necessary preliminary to the study of the distribution of the demarcation current and source is an examination of the character the resistance of the particular nerves in which phenomena are observe The resistance per cm. of the nerves examined—vagus, phrenic, an sciatic nerves of dog and cat, &c., varies with the nerve and with the animal the variations depending upon the character of the nerve and presunably of the individual fibres, upon its sectional area, and probably upon intrinsic differences between the average salt content of the tissues of different animals.