208 



Scientific Proceedings (128) 



B. The Preservation of Completely Parathyroidectomized Dogs. 

 Latent Tetany. 



Four of the completely parathyroidectomized dogs survived; 

 2 of them recovered spontaneously during milk feeding; the 

 other 2 recovered following vigorous calcium treatment com- 

 bined with milk feeding. In these latter dogs after a week or 

 two the doses employed (usually 1 or 2 grams of calcium chloride 

 a day intravenously) could be lowered and at last omitted; the 

 dogs lived without any symptoms and were to all appearance 

 normal on a milk diet. These 4 dogs could he kept alive inde- 

 finitely on this diet; one lived for 21 months and was then killed; 

 the others were either killed or at will brought into tetany from 

 which they died. These dogs which appeared absolutely normal 

 could, whenever it was wanted, be brought into tetany, usually 

 within 24 hours, by changing the diet to meat. This condition 

 formed an excellent opportunity for studying the various factors 

 involved in the production of tetany. Though to all appearances 

 normal these dogs showed one characteristic finding in the blood : 

 The calcium was still low. It varied to some extent, but was 

 usually between 5 and 6 mg. The inorganic phosphorus was 

 usually at the upper border of the normal level or above. Numer- 

 ous experiments have been performed on these dogs. 



1. The Diet in latent Tetany. On a milk diet (minimum 500 

 c.c. a day with bread or porridge) these dogs after the first criti- 

 cal period was passed could be kept without symptoms for as 

 long a time as wanted. Meat always produced tetany, loss of 

 appetite, and depression. Prolonged meat feeding killed two of 

 the dogs. Experiments with various forms of diet showed that it 

 was the withdrawal of milk which produced tetany, not meat diet 

 in itself, and the conclusion is, that milk contains substances which 

 prevent tetany. This substance proved to be calcium of which 

 milk contains 1.2 grams per liter, corresponding to about 10 

 grams of calcium lactate. Ninety per cent, of this calcium was 

 precipitated by sodium oxalate, care being taken not to get any 

 excess of oxalate in the milk, and this milk was now useless in 

 preventing tetany; usually within 24 hours the dogs got violent 

 tetany when fed this milk. 



2. Calcium Administration. On the other hand, if an amount 

 of soluble calcium salt was given corresponding to the Ca in the 



