418 SCIENCE PROGRESS 



the main organs. We can only reply that a most careful search 

 for such bodies has always been made, and that in the absence 

 of positive evidence their existence in any particular case can 

 only be purely conjectural. 



The operation of removing parathyroids without injury to the 

 thyroid is so difficult that in most cases it may be considered an 

 impossible one. It is to be noted, however, that removal of the 

 parathyroids, included of course in the complete operation, has 

 not proved fatal (in monkeys), so that if simple parathyroid- 

 ectomy is a fatal operation, it follows that removal of para- 

 thyroids alone is a more dangerous proceeding than extirpation 

 of the whole apparatus. This has in fact been alleged by some 

 observers. 



In 1875 Gull described a disease which he called "cretinoid 

 cachexia." Four years later Ord proposed the name " myx- 

 cedema," which has since prevailed. In 1882 and 1883 Reverdin 

 (23) and Kocher (24) observed symptoms very similar to those 

 of myxcedema in some of their patients from whom they had 

 removed the whole of the thyroid. Hence Reverdin called the 

 condition "operative myxcedema" (Kocher's designation was 

 " cachexia strumipriva "). 



In 1884 Horsley resumed the subject of experimental ex- 

 tirpation in animals which had been commenced by Schiff in 

 1856. Although, as will be gathered from the foregoing account, 

 the present writer has not been able to confirm the statements 

 of Horsley and his successors, Murray and Edmunds, that 

 removal of the thyroids from monkeys induces myxcedema, yet 

 it must be admitted that these experiments stimulated inquiry, 

 both experimental and clinical, and led to the employment of 

 thyroid given by the mouth in the treatment of myxcedema. This 

 method was first employed by Mackenzie (25) and Howitz (26). 



It must be noted that in the record of the Swiss surgeons, 

 " operative myxcedema " followed only in a certain number of 

 total removals of the thyroid gland. It would be interesting to 

 repeat the extirpation experiments, employing the anthropoid 

 apes for the purpose. 



(b) The question as to the relationship between thyroids and 

 parathyroids. — Some of the earlier observers looked upon the 

 parathyroids as simply undeveloped portions of the thyroid 

 tissue. The actual transformation of parathyroid into thyroid 

 tissue has been denied by the majority of investigators. But 



