338 



THE DUCTLESS GLANDS 



fCH. XXV. 



doubt forms an internal secretion ; to this the colloid material men- 

 tioned contributes, as it is found in the lymphatic vessels of the organ. 



When the gland is diseased in children and its function obliterated, 

 a species of idiocy is produced called cretinism, 



The same condition in adults is called myxcedema ; the most 

 marked symptoms of this condition are slowness, both of body and 

 mind, usually associated with tremors and twitchings. There is also 

 a peculiar condition of the skin leading to the overgrowth of the 

 subcutaneous tissues, which in time is replaced by fat ; the hair falls 

 off, the hands become spade-like; the whole body is unwieldy and 

 clumsy like the mind. 



A similar condition occurs after the thyroid is completely removed 



FIG. 280. Section of human thyroid; the few vesicles shown are lined by cubical epithelium, and con- 

 tain a colloid material. (After Bchiifer.) 



surgically ; this is called cackexia strumipriva ; this operation, which 

 was performed previous to our knowledge of the importance of the 

 thyroid, is of course not performed nowadays. 



Lastly, in many animals removal of the thyroid produces analogous 

 symptoms, in the overgrowth of the connective tissues especially 

 under the skin, a'nd in the nervous symptoms (twitchings, convul- 

 sions, etc.). 



The term Myxcedema was originally given under the erroneous 

 idea that the swelling of the body is due to mucin. In the early 

 stages of the disease there is a slight increase of mucin, because 

 all new connective tissues contain a relatively large amount of ground 

 substance, the most abundant constituent of which, next to water, 

 is mucin. But there is nothing characteristic about that. 



