58 INTERNAL SECRETION 



concerning the metabolism of lime. They investigated the entire 

 amount of lime, in both normal rats and those which had been 

 deprived of the parathyroid glands. The latter showed no change 

 which could be described as abnormal and there was certainly no 

 reduction in the quantity of excreted lime. They found, however, 

 that in young growing rats afflicted with tetany, the entire amount 

 of lime was less than in normal rats ; moreover, the proportion 

 of lime in the bones to that in the soft parts, was invariably lower 

 than in the control animal. The soft parts contained more lime, 

 the bones less, and this finding is in accordance with the histo- 

 logical changes in the bones and the teeth. 



As a matter of fact, a knowledge of the total amount of 

 calcium does little to furnish a solution of the problem, for it 

 supplies no information as to the amount of physiologically active 

 free kathions. Leopold and v. Reuss think that the results of 

 their experiments justify them in the belief that the amount of 

 active calcium in the organism is reduced in tetany. This might 

 occur as the result of the activity of the tetany toxin in pre- 

 cipitating calcium ; while at the same time the passive calcium 

 of the soft parts, which is ultimately excreted, is not only not 

 reduced but, by means of food rich in lime, may even be in- 

 creased. 



The relationship between tetany and the metabolism of cal- 

 cium, though not as yet fully understood, forms the basis of 

 the therapeutic treatment of tetany by means of calcium salts. 

 MacCallum and Vogtlin found that the administration of a 5 

 per cent, solution of calcium acetate and calcium lactate, whether 

 by the mouth or by intravenous or subcutaneous injection, to 

 dogs from which the parathyroids had been removed, was followed 

 by disappearance of the tetanic symptoms. The improvement 

 lasted twenty-four hours ; the convulsions then recurred, but these 

 were again subdued by a repetition of the treatment. Similar 

 results were obtained with magnesium salts, but in this case the 

 therapeutic effects were obscured by the anesthetic toxic by- 

 effects. Calcium salts increased the tetanic symptoms, but these 

 were reduced by the exhibition of larger doses. MacCallum and 

 Vogtlin are of the opinion that, taken in conjunction with their 

 discoveries regarding the excretion of calcium, these therapeutic 

 results point to an activity on the part of the parathyroid glands 

 in controlling the metabolism of calcium. They believe that, after 

 removal of the parathyroids, active calcium is withdrawn from 

 the tissues and that there is, in all probability, an imperfect 

 absorption and assimilation of calcium. Suppression of the 

 calcium-ions causes muscular convulsion similar to that produced 

 in normal animals by Loeb and MacCallum by the administration 

 of oxalates which, in combination with calcium, form insoluble 

 precipitates. In these cases also, the tetanic symptoms disappear 

 after the administration of fresh soluble calcium salts. 



