THE PAEATHYROID GLANDS 



523 



fatal, and would have made a statement to that effect, as positive as that 

 of MacCallum or of Paton. 



In 1911, however, the writer removed the thyroids, including the in- 

 ternal and the external parathyroids, from four lambs and four adult 

 sheep. The lambs all showed acute symptoms shortly after the operation 

 and died. In the case of none of the adult sheep were such results noted 

 during the time they were under observation three to four months. It 

 might be said that failure to produce tetany in the four sheep was due to 

 the fact that some accessory parathyroids had been overlooked at the opera- 



Fig. 1. Sheep (right) from which both lobes of thyroid, including internal para- 

 thyroids, and two external parathyroids were removed on Nov. 20, 1919, and twin 

 lambs born by this sheep on April 15, 1920. Photograph taken July 27, 1920. 



tion and were not discovered at the autopsy. It would be a strange coinci- 

 dence, however, if, by the same operator, all the parathyroids should be 

 removed in the four lambs, in which, in fact, they are more difficult to find 

 on account of the larger size of the thymus, and some left behind in each 

 of the four adult sheep. 



On November 20th, 1919, I performed the complete operation in four 

 adult sheep; left both external parathyroids behind in a fifth, removing 

 the thyroid, including internal parathyroids ; and kept a sixth untouched 

 as a control. Shortly after the operation all became pregnant, and two of 

 the four which are believed to have lost all thyroids and parathyroids are 

 alive, suckling lambs (one a pair) and to all appearance in perfect health 

 at the date of writing, July 27, 1920, neither having ever showed any 

 symptoms, (see Fig. 1). 



One, after dropping a dead fetus on April 2, showed signs of tetany on 



