PHILIP H. MITCHELL AND J. WALTER WILSON 



51 



500 cc. of solution were used. During the last 1| hours the muscles 

 of one leg were stimulated intermittently with strong induction 

 shocks applied to the distal end of the severed lumbar plexus. The 

 average potassium content of the muscles of the rested leg was then 

 found to be 0.350 and of the stimulated muscle 0.306 per cent. In 

 another experiment 2f liters of solution were perfused and stimulation 

 with intermittent rest periods was applied during 2| hours to one 

 leg. The average potassium content of the muscles of the rested leg 



TABLE m. 

 Loss of Potassiuvt front Muscles Perfused with Potassium-free Ringer Solution. 



* Figures in this column are obtained, as explained in the text, by computing 

 the difference between potassium in solids of control muscle and in those of perfused 

 muscle as per cent of the potassium in the solids of the control muscle. 



The frogs used in the first four experiments reported in this table were collected 

 in summer and used shortly after they were brought to the laboratory. Those 

 used in the last four experiments were collected in winter in Louisiana and used 

 some months later. 



was 0.299 per cent and of the stimulated leg 0.237 per cent. The 

 stimulated muscles show lower potassium content than the resting 

 ones. Siebeck's (11) observation, confirmed by Meigs and Atwood 

 (12), that a muscle in isotonic potassium chloride solution takes on 

 more weight if active than if at rest should be recalled in tliis 

 connection. The apparent losses of potassium in the stimulated 

 as contrasted with the rested muscles are not, indeed, greater than 

 could be accounted for as percentage changes due to absorption of 



