THE PAEATHYROID GLANDS 535 



tion. Sodium citrate, sodium oxalate (which precipitates calcium), and 

 sodium soap, have the opposite effect and greatly increase the excitability 

 of the cortex, so that the strength of stimulus needed to produce muscular 

 movements is much reduced. Any substance which precipitates calcium 

 has the same effect and, in sufficient concentration, may lead to spon- 

 taneous muscular twitchings and epileptiform seizures. One may apply 

 sodium citrate to the motor area of one hemisphere and calcium chloride 

 to that of the other, with the result that the excitability on one side is 

 markedly increased and on the other side diminished. Considering this 

 soothing influence of soluble salts of calcium, Sabbatani suggests it as 

 a remedy in epileptiform seizures. 



Howell studied the effects of depriving excised muscles of calcium 

 and exposing them to the action of calcium-free solutions, such as pure 

 sodium chloride. He noted that rhythmical contractions occur, which may 

 become tetanic, and that these can be checked by the addition of cal- 

 cium. 



Jacques Loeb found that the injection into animals of any salt which 

 will precipitate calcium and so diminish the amount of that substance in 

 solution in the tissues and fluids of the body, produces muscular twitch- 

 ing. Abnormal conditions, of metabolism might arise, such as the increase 

 of acid substances, which would thus reduce the quantity of calcium salts 

 and so lead to muscular disturbances, and he suggests the administration 

 of calcium in the treatment of such cases. He placed a frog's nerve- 

 muscle preparation in solutions of salts which either precipitate the cal- 

 cium, or render it inactive in some other way, and was able to show 

 records of muscular twitchings. These were immediately suppressed by 

 the addition of fresh calcium, or the transference of the preparation to 

 a solution of calcium of the requisite concentration. 



J. B. MacCallum pointed out that salts which are antagonistic to 

 calcium have the power of increasing the peristaltic activity of the in- 

 testine and increasing the secretory activity of certain organs, whereas 

 soluble salts of calcium have the opposite effect. 



Roncoroni showed that the reduction of calcium in the blood circu- 

 lating to the brain produced the same effect as was obtained by Sabba- 

 tani; the excitability of the motor cortex was greatly increased, provok- 

 ing epileptiform phenomena, which were quickly suppressed by the ad- 

 dition of the requisite amount of calcium to the circulating fluid. Ron- 

 coroni also examined the cerebral cortex, treated with various salts by 

 Sabbatani's method, and found no histological changes which were char- 

 acteristic. 



Dietary Studies on Calcium Deficiency and Tetany. Thiemich (6) 

 pointed out that tetany occurs most frequently in infants artificially fed 

 on cow's milk, and that it probably has something to do with calcium de- 

 ficiency, which may be associated with digestive disturbances. Japha 



