DIFFUSION AND OSMOSIS 5 5 



the muscular contraction. For this purpose I used a solution 

 freezing at — "53° C. and immersed in it untired muscles, and 

 muscles which had been electrically excited for two, four, and 

 six minutes respectively. The following are the results : — 



Untired muscles. Muscles stimulated once a second during 



2 Minutes. 4- Minutes. 6 Minutes. 



•Ooo . . +026 +-084 +-094 



+ •001 . . +-084 +-065 +093 



+ 005 . . +-045 +079 +097 



■000 . . +-037 +070 + 095 



•000 . . +-032 +072 +-096 



Mean of all the observations — 



+ •0012 . . +-0348 +'074 +-095 



These experiments show clearly that the osmotic intra- 

 muscular pressure rises in proportion to the duration of the 

 electrical stimulation. 



In order to determine the influence of the work ac- 

 complished by the muscle on the elevation of the osmotic 

 pressure, I made the following experiment. The two hind 

 legs of a frog were submitted to the same electrical excitation, 

 one leg being left at liberty, and the other being stretched by 

 a hundred-gramme weight, acting by a cord and pulley. After 

 exciting them electrically for five minutes, the legs were 

 immersed for twenty-four hours in a saline solution freezing at 

 •53° C. The free limb showed an augmentation of "085 of the 

 initial weight, and the stretched limb an increase of '106 of 

 the initial weight. It is evident, therefore, that the osmotic 

 pressure increases with the amount of work done by a muscle. 



Briefly, then, the results of our experiments are as follow : — 



1. Muscular contraction electrically produced causes an 

 increase of the osmotic pressure in a muscle. 



2. The intramuscular osmotic pressure may reach, or even 

 exceed, 2'5 atmospheres, or 2"G kilogrammes per square 

 centimetre of surface. 



3. When a muscle is made to contract once a second, the 



