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and then the muscle contracted. This period is called the period of latent stimulation. In the experiment we have just made, it does not Fig. 31.—Curve of a single muscular twitch as taken with the railway myograph. a to b, period of latent stimulation; b to c, contraction; and c to d, relaxation of muscle; e, small secondary wave, probably due to movement of lever. exactly represent the period during which the muscle rested after receiving the molecular disturbance of the nerve-current, as I have already explained, and we must deduct from it the time occupied by the nerve-current travelling down the little bit of nerve. However, it is interesting to know that there is a short period during which changes are probably happening in the muscle before it contracts. In the latent period, the muscle is preparing for making the movement. Very refined methods show that the latent period is shorter than the one-hundredth part of a second. Professor