454 



Dr. W. M. Fletcher and Prof. F. G. Hopkins. 



denied, and the actual quantitative evidence supporting it had been wholly 

 unsatisfactory. 



If a muscle so fatigued, and containing lactic acid, be now left at rest in an 



Hours 24- 48 72 96 



Fig. 5.- — The course of lactic acid production in an atmosphere of hydrogen at 12° C. 

 (Figs. 5, 6, and 7 from the ' Journal of Physiology,' vol 35, p. 273 (1907).) 



GED8 



Hours 5 lO 15 20 



Fig. 6.— The course of lactic acid production occurring during survival periods in 

 oxygen, air, hydrogen, and coal gas (CO) respectively. The two uppermost curves 

 are introduced for comparison of those for chopped muscle and for alcohol im- 

 mersion. 



oxygen atmosphere, a notable decrease of lactic acid occurs. The acid is 

 diminished quickly at first and later more slowly. It disappears, just as we 

 saw earlier that fatigue or the stiffening of early rigor mortis disappears, when 



