PARATHYROID GLANDS 73 



Leaving one parathyroid is usually sufficient to 

 prevent death, but tetany may stiU ensue. 



Changes in the human parathyroids are said to be 

 very frequent in cases of tetany in children or 

 pregnant women, and also in osteomalacia, in which 

 the inorganic matter of bone is largely removed. In 

 fact it is probable that the tetanj^ itself depends on 

 some abnormality of the calcium metabolism of the 

 body. The main function of the parathyroid glands 

 is perhaps to control the calcium metabolism. 



It would seem that in man, myxoedema is due to 

 loss of the internal secretion of the thyroid itself, 

 but that tetany and fatal symptoms in both man 

 and animals are due to loss of the parathyroids. 

 The convulsions of tetany in dogs may be arrested 

 by feeding on a watery extract of twelve to twenty 

 horses' parathyroids (Moussu). 



REMOVAL OF THYROID ALONE. 



Removal of the thyroid gland \\ithout the para- 

 thyroids is usually not fatal ; myxoedema results 

 in man ; occasionally, perhaps, in animals also, 

 but more commonly only cachexia. In young 

 animals, however, the results are much more dis- 

 tinct, and Eiselsberg and others have induced very 

 convincing cretinism, with a remarkable stunting 

 of growth, in lambs, goats, rabbits, and asses. It 

 is interesting and important to notice that the 

 animals so treated developed exceedingly marked 

 atheroma of the aorta, of which Eiselsberg gives 

 good figures. 



