Fig. 1

Results of analysis of galvanometer deflections obtained by stimulating frog sartorius muscles for 1.2 s (90 Hz) at 0 °C. The results show the rate of heat production in blocks of 0.2 s. These represent the first three phases, viz the heat production associated respectively with a the development, b the maintenance, and c the disappearance of the mechanical response. The recovery heat is not seen because it is very slow at low temperature. Heat production given in cal/g muscle. Hill and Hartree [57]. Although the analysis involved large corrections, the results are remarkably similar to those in later studies [59, 60]