[Reactive changes in the heat-resistant muscle tissue of lake frogs during heat acclimation].

A study was made of the effect of heat acclimation of animals on the individual changes in the muscle heat resistance in populations of Rana ridibunda belonging to European or Asiatic groups of the species. The relationship between the levels of heat resistance of muscle cells and the value of its changes are the same in the populations of these groups. It is believed that this relationship forms on the level higher than populational one.