Specific Energy of Nerves

A question of considerable interest to the psychologist is whether the impulses conveyed by different nerves are similar in nature. In other words, is the nerve impulse to be compared to a current of electricity, tile effect of which depends entirely on the mechanism with which it is connected, e.g. electric bell, electric light, etc.? The generally accepted belief, and the one which accords best with experimental facts, is that the impulse in all nerves is identical in kind, although of course it may vary in intensity, the various responses being determined solely by the different terminations.

According to the opposite theory the impulse varies with the nature of the nerve, the character of the impulse being different in a sensory nerve from that in a motor nerve, etc.