RHYTHMICAL CONTRACTIONS IN MUSCLE 525 



higher degree than in the case of Na ions, since, according 

 to Gaule, only a trace of NaOH or Na 2 CO 3 favors the 

 rhythmical activity of the heart. The same favorable effect 

 of the HO ions shows itself also in the rhythmical contrac- 

 tions of skeletal muscle. 



When a muscle is introduced into a 0.7 per cent. NaCl 

 solution, the rhythmical contractions of individual fibers or 

 the entire muscle begin after about sixty to ninety minutes. 

 If a trace of alkali is added, however, contractions begin 

 much sooner. I will give an example. In one series of ex- 

 periments the muscle began to beat rhythmically after 

 twenty-seven minutes in 100 c.c. of a 0.7 per cent. NaCl 

 solution to which had been added 2 c.c. of a one-tenth 

 normal LiOH solution. In 100 c.c. of a NaCl solution of 

 the same concentration to which had been added 3 c.c. of a 

 one-tenth normal LiOH solution weak rhythmical contrac- 

 tions began immediately. In 100 c.c. of a 0.7 per cent. 

 NaCl solution to which had been added 4 c.c. of the same 

 LiOH solution strong rhythmical contractions began imme- 

 diately. In the 0.7 per cent. NaCl solution (to which no 

 LiOH had been added) it required seventy-two minutes be- 

 fore rhythmical contractions began. Other series of ex- 

 periments yielded similar results. This shows without a 

 doubt that LiOH accelerates the appearance of rhythmical 

 contractions. That we are, indeed, dealing only with the 

 action of the hydroxyl ions is shown by the fact that it does 

 not matter what alkali is added (for example, LiOH, KOH, 

 NaOH, etc.), as long as the degree of dissociation is the 

 same. 



It might be concluded from this that the hydroxyl ions 

 indeed belong to that class which of themselves are able to 

 bring about rhythmical contractions, for the rhythmical con- 

 tractions which occur immediately can be caused only by the 

 hydroxyl ions. 



