538 SUTHERLAND SIMPSON 



the tissues, and cause its excretion, and that the parathyroid secretion 

 prevents the appearance of such bodies. The mechanism of the parathy- 

 roid action is not determined, but the result, the impoverishment of the 

 tissue with respect to calcium, and the consequent development of hyper- 

 excitability of the nerve cell, is proven. Only the restoration of calcium 

 to the tissues can prevent this." 



In a paper published also in 1909, Berkeley and Beebe (a) dispute the 

 conclusions of MacCallum and Voegtlin, and incline toward the belief 

 that the symptoms which follow parathyroidectomy are not caused by any 

 deficiency of calcium in the tissues, but rather by some metabolic toxin, 

 which is ordinarily destroyed or neutralized by the physiological activity 

 of the parathyroids. They found, as MacCallum and Voegtlin had 

 shown, that intravenous injections of a soluble calcium salt will relieve 

 the symptoms almost instantly, even in advanced stages of tetany; it is, 

 they say, one of the most striking results in the range of physiological 

 experimentation. Intramuscular injections were effective after thirty 

 to forty-five minutes, and a similar period is required for the beneficial 

 influence after subcutaneous injection. This effect is, however, only tem- 

 porary. 



The symptoms in the acute stage, according to these observers, point 

 strongly to a . poison which acts somewhat like those of the convulsant 

 series, including strychnin, ammonia, and the various xanthin substitu- 

 tion products, Berkeley and Beebe point out that the muscular twitch- 

 ing which takes place when isolated muscle is immersed in calcium-free 

 normal saline solution is of peripheral origin, and can hardly be con- 

 sidered as evidence in a theory to explain an action which is central 

 in origin. In contravention to the claim that a milk diet tends to delay 

 or ameliorate the symptoms on account of its high calcium content, 

 these same investigators declare that some of their animals on a meat 

 diet after operation were given bone ash, so that the calcium intake was 

 much larger than that afforded through a milk diet, and yet these bone 

 ash fed animals had the same tetanic seizures as those fed on meat with- 

 out bone ash. 



In certain pathological conditions, such as diabetic acidosis, there is 

 known to be a large excretion of calcium sometimes twice the normal 

 and yet no tetany develops. If this increased excretion of calcium, which 

 may take place over extended periods, can continue without causing 

 tetany, why should a two days' excessive excretion, such as might occur 

 after parathyroidectomy, produce these symptoms, they ask, especially 

 when there is such an abundant store of calcium in the bones of the skele- 

 ton to be drawn from ? 



Another observation, originally made by MacCallum, which Berkeley 

 and Beebe were able to confirm repeatedly, was that, when an animal, 

 in the acute stage of tetany, has approximately one-third of its blood 



