54 THE MECHANISM OF LIFE 



This result shows that muscular work provoked by electric 

 stimulation noticeably increases the osmotic pressure of the 

 muscle. 



In order to discover the exact osmotic pressure in the 

 stimulated muscles we repeated the series of experiments, using 

 more and more concentrated solutions. In a solution whose 

 freezing point was — "57°, we obtained the following values : — 



Change of weight of untired leg — ■ 



After 8 hours - -000. 

 After 16 hours - '004. 

 After 24 hours - -006. 



Change of weight of stimulated lea; — 



'5 



After 8 hours + 039. 

 After 16 hours + -072. 

 After 24 hours + -099. 



Finally, in a solution freezing at — '72°, i.e. with an osmotic 

 pressure at 1-5° C. of 9'176 atmospheres, we obtained the 

 following mean values for the untired leg : — 



After 8 hours -04. 

 After 16 hours - -05. 

 After 24 hours — -05. 



In this solution, freezing at — "72° C, some of the stimu- 

 lated muscles showed no diminution in weight, while others 

 showed a very small diminution, and others again a slight 

 augmentation, the maximum increase being "085 of the 

 initial weight. The solution is therefore practically isotonic 

 with the stimulated muscle. 



In this case the elevation of the intramuscular osmotic 

 pressure produced by the electrical excitation and the muscular 

 contractions was therefore 2'5 atmospheres, or more than 26 

 kilogrammes per square centimetre of surface. 



I made further experiments in order to discover whether 

 the variation in osmotic pressure depended on the duration of 



