132 MOVEMENT 



When processes of oxidation are diminished, as by potassium 

 cyanide, a muscle is still able to contract, but lactic acid 

 accumulates more rapidly than in normal muscle. Apparently, 

 therefore, in normal muscle, part of the lactic acid is utilized 

 (oxidized) to reconvert the remainder (about five-sixths) into 

 glycogen, which greatly increases the efficiency of muscle. In 

 severe exercise the lactic acid escapes into the blood and is 

 excreted in the urine. If all of it were disjoosed of in this 

 way, contraction — though inefficient — would be entirely 

 anaerobic. 



