receives a shock, and it again contracts. Then it again relaxes; but it does not relax so much as before, ere it receives the third shock, and
Fig. 33.—Curves showing the production of tetanus, as taken in the rapidly moving plate of the railway myograph. Observe in all the experiments from a to e the muscle had time to relax between the shocks; at f tetanus began to appear, and in g it was complete. The curves here shown are one-fifth of their real size. successive steps become smaller and smaller as we ascend (see Figs. 34, 35, and 36).
By shortening the spring, we quicken the period of its vibration, and thus we increase the number of shocks per second. Now you observe the individual contractions are smaller and closer together; but if we look at the tracing carefully, we find the same stair-like character of the curve, only the steps are smaller (Fig. 35). Again, still further shorten
