THE THYROID GLAND AND ITS DISEASES 227 



was sent to him as "myxedematous." The animal had nothing more than 

 an ill-defined facial swelling, probably due to a carious tooth, and an 

 intermittent paresis of a fore limb. The animal was, according to Munk, 

 otherwise in good health and lived for ten months after the operation. 

 Munk insisted that although removal of the thyroid is a dangerous opera- 

 tion, it does not follow that the thyroid is absolutely essential to life. And 

 this statement must be admitted as justifiable, even if the survivals are 

 due to thyroid or parathyroid tissue which is so placed that it cannot be 

 removed. It will be necessary to return to this point. 



The further account of Gley's work, as well as that of Vassale and 

 Generali and Kohn, will be found in the section on the physiology of the 

 parathyroids. 



The experiments of Vincent and Jolly may be briefly recalled so far as 

 they relate to the general question of extirpation of thyroids and para- 

 thyroids, and more particularly in regard to the effects alleged to be due 

 to elimination of the function of the thyroid. On these points the general 

 conclusions were: "Neitherr.thyroid nor parathyroids can be considered as 

 organs absolutely essential )or life. Rats and guinea-pigs do not seem to 

 suffer at all as the result of [extirpation. Monkeys show only transient 

 nervous symptoms. Dogs, oats, foxes and prairie wolves frequently suffer 

 severely and die. On the other hand, badgers do not appear to be affected 

 by the operation. 



"In no animals, not even in monkeys, have we been able to induce any 

 swellings of the subcutaneous tissue, which is the most striking feature of 

 myxedema in the human subject. We think, therefore, that the pathology 

 of myxedema in the human subject must be more complex than simple 

 thyroid insufficiency." 1 . . .. . . 



Several previous observers from Schiff onwards had noted the fact that 

 thyroidectomy in dogs and cats is by no means always fatal. At the same 

 time there has been a tendency to disregard the exceptions, and when 

 any explanations have been offered it has been suggested that they are due 

 to parathyroids having been overlooked at the operation, or to the existence 

 of accessory thyroids. Munk (vide supra) indeed is among the few ob- 

 servers who have laid due stress upon the cases of survival. This observer, 

 as we have seen, admits that removal of the thyroid is dangerous, but not 

 that the gland is an organ essential to life. We cannot assail the logic 

 of the position that an organ which may frequently be removed with 

 impunity is not "essential to life" and the results obtained by Vincent 

 and Jolly forced them to extend the observation so as to include not only 

 one thyroid but also the parathyroids. 



According to Noel Paton a "contention that the removal of the para- 



J 0n other points discussed in these papers the present writer has changed his 

 opinion. This applies to the change of parathyroid into thyroid. 



