9 6 



Scientific Proceedings (65). 



59 (99i) 



The effect of thyro-parathyroidectomy on the blood coagulation 

 time in the dog. 



By Sutherland Simpson and A. T. Rasmussen. 



[From the Department of Physiology and Biochemistry, Medical 

 College, Cornell University, Ithaca, N. Y.] 



It has long been held that the parathyroid glands are in some 

 way concerned with the metabolism of calcium in the body. In 

 dogs killed during parathyroid tetany MacCallum and Voegtlin 1 

 found a decrease in the amount of calcium contained in the blood 

 and brain tissue, and recently MacCallum, Lambert and Vogel* 

 have shown that when blood, from which the calcium has, in large 

 part been removed by dialysis, is perfused through an isolated 

 limb, the nerves of this limb show extreme hyperexcitability similar 

 to that observed in tetany. 



It is also believed by Wright and others that a diminution of 

 ionic calcium in the blood leads to a prolongation of the coagulation 

 time, and an increase to a shortening of the time. 



Our experiments were undertaken with the object of deter- 

 mining whether removal of the parathyroids (and thyroids) in 

 the dog will produce any effect on the speed with which the blood 

 coagulates, and so presumably, point to a change in its calcium 

 content. 



We adopted the graphic method of Cannon and Mendenhall 3 

 of estimating the coagulation time, with one or two slight modi- 

 fications, and found it to work satisfactorily. 



The dog was anesthetized with ether, the left saphenous artery 

 clamped close to the femoral from which it arises, ligatured on the 

 distal side and then opened between the clamp and the ligature. 

 The coagulation tube or canula was made so that it fitted tightly 

 into the central end of the incision, and on relaxing the clamp a 

 sample of circulating blood was obtained. The canula was then 

 plugged with plasticine, quickly removed to a waterbath kept at 



1 MacCallum and Voegtlin, Jour. Exper. Med., 1909, XI, p. 118. 



s MacCallum, Lambert and Vogel, Jour. Exper. Med., 1914. XX, p. 168. 



3 Cannon and Mendenhall, Amer. Jour. Physiol., 1914. XXXIII, p. 225. 



