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28 for an instant and you hear one stroke of the bell. Another shock causes another twitch; and we find that if we allow some time to elapse between successive shocks, there is a twitch with each shock. But the twitch is so

fast, it occurs in so short a time, that the eye can scarcely follow it, so that we cannot see what the muscle really does. But I now send a rapid series of shocks, and you observe that the muscle has become shorter and thicker. It has also pulled on the thread of the telegraph,