494 The University Science Bulletin. 



surface-tension-lowering substance. That such an explosive break- 

 down is peculiar to the contraction is clearly indicated by corre- 

 lating these observations with those of Fletcher. Fletcher has found 

 that lactic acid is liberated during the contraction phase of muscle. 

 I find that lactic acid increases the surface tension of the cells. It 

 causes the cell to contract. This lactic acid disappears again dur- 

 ing the intermittent rest period. The cell again returns to its former 

 state. The process is rhythmical. The process, as it is evident, is 

 somewhat similar, therefore, to the phenomenon described by Bredig. 

 Bredig showed that when a ten per cent solution of H2O2 is placed 

 over the surface of pure mercury, a film of mercury peroxide forms 

 at the surface. This leads to electrical changes in this system. 

 Under appropriate conditions the peroxidate breaks down again 

 to mercury and oxygen. Then the layer of peroxidate reforms. The 

 process is repeatable or rhythmical. Bredig and his students further 

 find that many conditions which alter rhythmical muscular con- 

 traction also alters the activity of this model.^^ 



Rhythmical muscular contraction is not, therefore, as Bayliss sug- 

 gests, the result of rhythmical stimuli, but evidently the result of 

 an explosive breakdown leading to alternate changes, not only in 

 surface tension, but in the electrical conditions at opposite ends of 

 the cell. Bernstein'^" several years ago had given definite evidence 

 to show that the energy of muscular contraction is surface energy. 

 He found that muscles suffer the thermal changes peculiar alone to 

 surface energy. 



In such organization, as it -is well recognized, there is no reason 

 that such an explosive breakdown should always occur. Such is 

 possible only when the decrease in surface tension at the free end 

 or the electrical changes are of such a degree to allow a current to 

 pass through the resistent cell. This change at the free end may 

 cease before such is possible. For a breakdown to take place other 

 special conditions or stimuli must be present. That this is the con- 

 dition of most of the functioning tissue of the body has been well 

 proven by the studies of tissue autonomy. In man, whether any 

 muscular tissue, other than the nodes of the auricle, are autonomous, 

 like the cell of the culture, I think is questionable. At the same 

 time it is evident that any functioning tissue may develop such a 

 condition. Whether this is what has happened in many of the 

 nervous affections might be a problem worth investigating. It is 

 not surprising, however, that in other animals the autonomy is 

 centered in other tissues. Carlson^^ finds that the rhythm of 

 the heart of the limulus is not automatic, but centered in certain 



