Page:Life in Motion.djvu/121

Rh without the influence of nerves. This beautiful experiment was devised by the eminent French physiologist, Claude Bernard, and conclusively proves the truth of Haller's theory.

A muscle, then, contains contractile stuff, and this stuff is thrown into molecular activity by the nerve. The nerve-current, or nerve-shock, is the natural stimulus of the muscle. So long as the muscle is irritable, it responds to this stimulus, and the obvious response it makes is a change of form, or a contraction.