THE PARATHYROIDS 45 



Koch has found that in tetany there is an ex- 

 cessive elimination of guanidine, an important 

 nitrogenous substance that plays a part in the 

 metabolism of the body ; and he has postulated the 

 theory that tetany is due to an intoxication of the 

 central nervous system by this guanidine, a view 

 that has a number of opponents. 



It may now be asked, if hyper-secretion of the 

 thyroid may give rise to exophthalmic goiter, what 

 does hyper-secretion of the parathyroid give rise 

 to? We are not very sure. We have reached the 

 end of the land of fact and have now begun our 

 journey in that of speculation. Since one of the 

 chief objects in writing this book is to distinguish 

 fact from fancy, and therefore to combat much that 

 has been written on the subject of the ductless 

 glands, we shall avoid entering this land of specu- 

 lation. 



The study of the parathyroids makes clear why 

 in operations involving the removal of thyroid tu- 

 mors, the earlier surgeons were much troubled, 

 because very often an apparently successful opera- 

 tion would be marred by the development of tetany 

 in the patient. We now can attribute such a re- 

 sult to the removal of the parathyroids as well as 

 to that of the thyroid. The surgeon of the present 

 day, engaged in an operation of this kind, invari- 

 ably leaves at least two of the four parathyroids, 

 for not the least remarkable of the many remark- 



