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." 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. 
Il 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 
1 SABBATANTI 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 Biologie, 
Vol. XXXVI (1901), p. 397. 
Digitized by Microsoft® 
