38 INTERNAL SECRETION 



which differ radically, both in their symptom-complex and in the 

 course which they run. Of these conditions, one appears 

 promptly and is attended by violent muscular spasms. It is 

 obviously a disease affecting the nervous system and has been 

 called "tetany," on account of its resemblance to a well-known 

 idiopathic disease of man. The second condition is more chronic 

 in its development and is characterized by nutritional disturbances 

 of the most varied description. In man there is a peculiar 

 cedematous swelling of the skin, a decrease in mental power, and, 

 in young people, a remarkable arrest of development. This 

 condition was named myxoedeme postoperatoire by Reverdin, and 

 by Kocher, general cachexia strumipriva or thyropriva. These 

 two conditions were not regarded as separate pathological 

 entities, but as etiologically and pathogenetically the same. For 

 either might make its appearance in man after extirpation of the 

 thyroid gland, and transition forms between the two conditions 

 were known to exist. 



It seemed a remarkable thing that the suppression of an 

 organic function should be expressed by means of two totally 

 different symptom-complexes. Experiments with animals were 

 undertaken to show that this was due to the operation of factors as 

 widely divergent as species, age, external conditions such as 

 temperature, and nutrition. The latter appeared to be the deciding 

 factor ; for it was invariably found that removal of the thyroid in 

 the carnivorse caused death, while in the herbivoras it only pro- 

 duced nutritional derangements, these taking the form of chronic 

 cachexia, or, in young animals, disturbance of growth. 



The discovery of the parathyroid glands by Sandstroem in 

 1880 first provided a means of interpreting this difference in its 

 relation to species. A long time, however, elapsed before any- 

 thing was done in this direction. It was not until 1890 that the 

 French physiologist, E. Gley, was able to show that herbivorous 

 animals, such as rabbits, develop tetany if, in addition to the 

 thyroid, the parathyroid glands, which lie at some distance away 

 at the side of the carotid artery, are also removed. 



The anatomy of the thyroid glands was finally cleared up 

 by experiments undertaken by A. Kohn ; and, in 1896, Vassale 

 and Generali showed that in the dog, extirpation of all the 

 parathyroids was followed by tetany, while extirpation of the 

 thyroid was unattended by pathological signs. These results 

 were confirmed in many directions (Rouxeau, 1896; Gley, 1897; 

 Moussu, 1897; Welsh, 1898; Capobianco, 1899), but there was 

 considerable divergence of opinion as to their interpretation. 

 Surgeons were by no means unanimous in conceding to the 

 parathyroid glands a pathogenetic significance in tetania strumi- 

 priva. 



My own experience has shown that, not only does tetany 

 follow extirpation of the parathyroid glands, but that extirpation 



