An American text-book of physiology . FiG. 47.—Effect of frequent excitations to gradually produce tetanus. Experiment on a gastrocnemiusmuscle of a frog, similar to the last. The weight was only in grams. The rate of excitation was 100 perminute. Tliis muscle had been worked a short time before this series of contractions was taken, and, asa result, the introductory and staircase contractions were absent and contracture began much soonerthan in the experiment recorded in Figure 45. The record in section 6 is a continuation of that insection a. tracture was more marked than in the above experi
An American text-book of physiology . FiG. 47.—Effect of frequent excitations to gradually produce tetanus. Experiment on a gastrocnemiusmuscle of a frog, similar to the last. The weight was only in grams. The rate of excitation was 100 perminute. Tliis muscle had been worked a short time before this series of contractions was taken, and, asa result, the introductory and staircase contractions were absent and contracture began much soonerthan in the experiment recorded in Figure 45. The record in section 6 is a continuation of that insection a. tracture was more marked than in the above experiment, and the resulting con-dition of continued contraction caused first incomplete and finally completetetanus. Although frequent excitations appear to be essential to the development ofcontracture, it is doubtful whether it is to be considered a fatigue effect, since. Fig. 48.—Development and fatigue of contracture. Exi>eriment on a gastrocnemius muscle of a weight was 10 grams. As in the preceding experiments strong maximal breaking induction shockswere used to excite. The rate of excitation was 5 per second. The record appears as a silhouette for thereason that the drum was moving very slowly. the contracted state which it produces may be increasing at the time that fatigueis lessening the height of the ordinary contraction movements, and since the GENERAL PHYSIOLOGY OF MUSCLE AND NERVE. 117 form of coutraction peculiar to contracture is itself seen to lessen as fatiguebecomes excessive. Both of these facts are illustrated in Figure 47, but aremore strikingly shown in Figure 48, in which a more rapid rate of excitationwas used. The record in Figure 48 shows many points of interest: a to h, a rapidlydeveloping staircase, which is accompanied by a rising of the base line, whichindicates that contracture began to make itself felt from
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