PARATHYROID GLANDS 71 



cause exophthalmos. True myxoedema is not often 

 seen in the experimental animals. It has been 

 induced in mild degree in monkeys by Horsley, 

 Edmunds, and others, but not with any constancy, 

 and in other animals it is not seen at all. 



It is not usually possible to save the Hves of dogs 

 or monkeys whose thyroids have been removed, 

 by feeding on sheep's thyroid, although a good deal 

 of reUef may be obtained for the symptoms in tliis 

 way. Grafting a piece of the gland under the skin 

 is successful for a while, but eventually it is absorbed. 



The effects of removal of, or insufficient secretion 

 by, the thyroid gland in man are myxoedema, and 

 occasionally tetany. 



In 408 cases in Kocher's clinic at Berne complete 

 extirpation of the thyroid was followed bj'- myxoedema 

 in 69 cases, and a similar operation in 78 cases in 

 Billroth's clinic was followed by tetany in 13 cases, 

 of which 6 proved fatal. Feeding with sheep's 

 th5n-oid is wonderfully successful in myxoedema, 

 but is not usually effectual in tetany. 



Partial removals of the thyroid in dogs produce 

 symptoms of correspondingly lessened severity. 

 Halstead found that in one case one-eighteenth of 

 the gland sufficed to ward off symptoms of 

 athyroidism, but the amount wliich could safely be 

 left varied in different animals. One bitch which 

 had lost two-thirds of her total thyroid became 

 pregnant by a healthy male, and all her whelps had 

 enormous goitres, a fact which has also been 

 observed by Edmunds. 



Histological examination of the portion remaining 



