MUSCULAR TWITCHINGS 753 



the most favorable salts to produce rhythmical twitchings. 

 Sodium citrate does not precipitate calcium in the tissues, but 

 prevents its precipitating other compounds, and therefore 

 practically makes calcium inactive. 1 But that the precipitation 

 and inactivation of calcium is perhaps not the only factor 

 involved is shown by the efficiency of sodium formiate. It 

 may be, however, that sodium formiate undergoes further 

 changes in the tissues, and that one of the products formed 

 acts upon calcium. 



All these facts suggest that it might be worth while to 

 test the idea whether or not the pathological cases of mus- 

 cular hyperactivity and twitching are due to a lack of cal- 

 cium in the muscles (or blood), and whether the evil can be 

 mitigated by giving calcium salts to such patients. Experi- 

 ments must be made in animals to find out whether or not 

 such a treatment would do any harm before any therapeutical 

 experiments on patients should be attempted. It is our in- 

 tention to take up these experiments in the laboratory. 



II. THE DIFFERENT EFFECTS OF CALCIUM IN THE CASE OF 

 MYOGENIC AND NEUROGENIC RHYTHMICAL CONTRACTIONS 



1. While it seems easy to suppress, by the addition of 

 Ca, Sr, and Mg, rhythmical twitchings which originate in 

 the muscle itself, the question arises whether the same 

 means allow us to suppress, with equal ease, muscular twitch- 

 ings which originate through the central nervous system. 

 The simplest organism in which this can be tested is probably 

 the jelly-fish. These animals contract rhythmically. Their 

 central nervous system is contained in the margin of the 

 swimming-bell, while the center of the animal is said to con- 

 tain no nerve-elements except scattered neurons. By a cut 



l SABBATANI has shown that although sodium citrate does not precipitate cal- 

 cium, it renders it inactive. In the presence of a sufficient quantity of sodium 

 citrate, calcium loses, e. g., its coagulating effect: Archives Italiennes de Biologic, 

 Vol. XXXVI (1901), p. 397. 



