K and Ca in muscle mechanics, II. K-contracture.

K-rich solution, the isotony of which corresponds to normal Ringer's solution, was used in our experiments: 4.59 g KCl + 40.5 g saccharose, 1000 ml bidistilled water. Freshly prepared living muscles of Rana esculenta (m. sartorius, m. iliofibularis, m. peroneus, m. tibialis, m. gastrocnemius, m. semimembranosus) got into K-contracture in this solution, but they relaxed within some minutes. In muscles of dead frog (which canno tbe stimulated with 110 V a.c.) the K-rich solution did not elicit contracture, i.e. on the one hand K-contracture could be observed only in living muscle and on the other hand, the muscles did not lose their excitability after the K-contracture had ceased (a.c. 2V).