Muscunar Twitcuinas 749 
soluble calcium salt, the twitchings will not occur, though 
the muscle lives longer in such a solution than in a pure 
sodium-chloride solution. I concluded from this that we 
owe it to the calcium ions in the blood that our muscles do 
not twitch or beat rhythmically like our heart.! 
To test this idea further, Mr. W. E. Garrey and I under- 
took, in 1889, a series of experiments, not yet published, on 
the behavior of muscles in solutions of sodium salts whose 
anions precipitate calcium. The muscle itself contains cal- 
cium salts, and we considered it likely that these calcium 
salts might help in preventing contractions. We therefore 
thought that by putting the muscle into solutions of sodium 
salts, which, by entering the muscle, precipitate the calcium 
contained in it, we might produce still more powerful rhyth- 
mical contractions than in a pure sodium-chloride solution. 
This was found to be true. In solutions of sodium-fluoride, 
-oxalate, -carbonate, -phosphate, etc., of the proper concen- 
tration (1 gram-molecule in 8 liters of the solution), we 
obtained similar, but more powerful, rhythmical contractions 
than in sodium-chloride solutions of the same osmotic pres- 
sure. Another series of observations confirms the idea that 
it is due to the calcium salts in our body that our muscles do 
not show any rhythmical contractions or twitchings. When 
we inject into the body of an animal any salts that are liable 
to precipitate calcium, we notice ‘almost immediately twitch- 
ings of all the muscles.” It seems, therefore, rational that in 
the pathology of muscular twitchings the concentration of 
the calcium ions in the blood should be taken into considera- 
tion. It is quite possible that abnormal conditions may arise 
in the body which lead to an increase of such acids in the 
circulation as diminish the amount of calcium ions in the 
1Part II, p.518. See alsoS. RINGER, Journal of Physiology, Vol. VII (1886), p. 291 
In this paper Ringer also mentions briefly the fact that Ba differs in its action from 
Ca and Sr. 
2FRIEDENTHAL, Engelmann’s Archiv, 1901, p. 145. 
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