304 THE DUCTLESS GLANDS 



the few observers 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 the thyroid but also the parathyroids. 



According to Noel Paton, a * * contention that the removal of 

 the parathyroids does not produce the train of symptoms 

 terminating fatally, must in the light of the work of other 

 investigators be explained as due to a failure to remove all the 

 parathyroid tissue." Now, in the case of rabbits, Paton quotes 

 Pepere to the effect that accessory parathyroids are nearly 

 always found in the thymus in rabbits. So that in rabbits 

 parathyroidectomy is only fatal in the few animals which 

 happen not to have any parathyroid tissue in the thymus. 



In the monkeys employed by Vincent and Jolly no symptoms 

 of myxoedema were observed when thyroids and parathyroids 

 were completely removed. These results differ from those 

 obtained by Horsley (loc. cit.), Murray and Edmunds, who state 

 that it is possible to induce myxoedema by operation. This m ay 

 be compared with the results obtained by Munk (vide supra) and 

 Kishi. The last named only recorded one death out of six. Our 

 animals were subject to catarrh, and one died of some laryngeal 

 affection, and it seems probable that as in the case of other 

 animals, removal of the thyroid gland leaves monkeys in a 

 condition in which they are less capable of resisting disease. 

 There is no reason to attribute death, when it occurred, to 

 loss of thyroid or parathyroid. The animals were in good 

 health, were active, and but for loss of weight showed no ill 

 effects. 



Carlson and Woelf el report that myxoedema does not develop 

 in thyroidectomized rabbits, at least in seven months, nor in 

 the monkey in several months. 



In some groups of animals age seems to make a great differ- 

 ence to the results both of thyroidectomy and of ' ' complete ' ' 

 thyro- parathyroidectomy. Sutherland Simpson found that 

 removal of the thyroid with the contained internal parathyroids 

 in thirteen adult sheep and sixteen lambs from seven to eight 

 months old, led to practically no ill effects (see Fig. 88). As a 



