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Difficulties of present nomenclature.—We shall deal later with a method by which a responsive current of action is obtained without any antecedent current of injury. ‘ Negative variation’ has then no meaning. Or, again, a current of injury may sometimes undergo a change of direction (see note, p …

… This current of response flows, then, in the same direction as the existing current of reference —the current of injury—and may therefore be called positive. Unfortunately the current of injury is very often apt to change its sign; it then flows through the eye from the cornea …

… Accurate determination of the death-point by mechanical and electrical spasms—Current of injury due to after-effect of stimulus— Explanation of characteristic electric distribution in plant and muscle cylinders—Relative positivity of dead tissue—Reversal of current of injury so-called—Unreliability of response by negative variation.

In that case in which response becomes enfeebled, with the gradual decline and vanishing of the current of injury, a simple explanation is often applicable. When the tissue is injured, it does not necessarily die. In fact, I have often found that, in order to ensure death—in …

… The resultant upward response here is, then, in the same direc- tion as the so-called ‘ current of injury, and forms, as it were, a positive variation of it.

Electric response to direct stimulation — Response abolished under narcotics — Characteristics of transmitted impulse — Positive response in non-conducting or semi-conducting tissues — Diphasic and Monophasic response — Response by negative variation of current of injury — Monophasic response by method of natural block — Stimulation by ttiermai shock — ^The petiole-laminar …

… I shall have occasion in the present chapter to give a simple explanation of this phenomenon and of the excitatory nega- tive variation of the current of injury. It is, therefore, only necessary to recapitulate briefly the three theories which have hitherto been proposed on this subject.

… Record showing Inversion of Electric Curve (represented by dotted line) and Simultaneous Reversal of Electric Response in Stem of Amaranth { indicates current of injury from injured to uninjured contact, which, Normal

It is my intention to show in the course of the present chapter that the current of injury is an after-effect of over-stimulation. And since excitation is fundamentally due to molecular upset, we shali best understand the electro-motive changes concomitant with it, if we first …

Anomalies of present terminology.—When there is no current of injury, a particular current of response can hardly be called a negative, or positive, variation. Such nomenclature is purely arbitrary, and leads, as will be shown, to much confusion. A more definite terminology, free from misunderstanding, would be …

… i) Conditions for obtaining electric response—Method of injury—Current of injury—Injured end, cuproid: uninjured, zincoid—Current of response in nerve from more excited to less excited—Difficulties of present nomenclature—Electric recorder—Two types of response, positive and negative—Universal applicability of electric mode of response …

INJURY, degree determining sign of action current, 175 _ see Current of Injury . Interference, induced difference of phase causing, 142 af method of: effect of chemical agents determined by, 147 * Be effect of cold determined by, 147 Inversion of thermo-mechanical curve, 198 “f of electro-motive curve, 202 …

… From this it follows, that the so-called current of injury will flow in the tissue from the neighbourhood of the cut, to the distant and relatively un- excited end. The current of injury is thus an after-effect of strong stimulus. The peculiar electrical distribution which occurs …

… Thus, without the postulation of any electro-motive mole- cules so-called, these experimental results afford a simple and direct explanation of the so-called current of injury, as the excitatory after-effect of strong stimulation.

Conditions for obtaining electric response— Method of injury —Current of injury—Injured end, cuproid: uninjured, zincoid—Current of response in nerve from more excited to less excited—Difficulties of present nomenclature—Electric recorder—T wo types of response, positive and negative —Universal applicability of electric mode of response …

… Action current—We have seen that a current of injury—sometimes known as ‘current of rest —flows in a nerve from the injured to the uninjured, and that the injured B is then less excitable than the uninjured A. If now the nerve be excited, there being a …

… After a while the current of injury was found to disappear. On exciting the stem by taps or torsional vibration, a responsive current was observed which flowed inwards from the more disturbed outer surface to the shielded core inside (fig. 29). Henee it is seen that when a …

… For we may obtain the usual response when the current of. injury is zero, or even positive. In fact, the only essential condition for the obtaining of resultant response is that at one contact the excitability should be in a state of relative depression.

… We have further seen that in such a case the response to external stimulus is by a negative variation of the current of injury. We have next, then, to take up various instances which appear highly anomalous, cases, that is to say, in which the injured point, relatively …

… will thus arise of a ‘ positive’ current of injury, so-called. Anomalous case of response by positive variation—Inquiry into the cause— Electric exploration of dying and dead tissue : death being natural—Determi- nation of electric distribution in tissue with one, end killed—Dying tissue shows maximum negativity …