482 POPULAR SCIENCE MONTHLY. 



the other ductless glands (the spleen, the thymus, and the adrenal 

 bodies), is but imperfectly understood. I shall limit myself to 

 saying that the presence of the normal thyroid gland is neces- 

 sary for health, and that it is supposed that the secretion of the 

 gland, which enters the blood- current directly, either neutralizes 

 some poison which, from the ordinary processes of life, is circu- 

 lating in the blood, or furnishes to the blood some substance 

 which is necessary to it. When from any cause this function of 

 the gland is interfered with, very characteristic symptoms result. 

 It is only within recent years that it has been recognized that 

 impairment of thyroid function can and does cause a definite 

 group of symptoms which constitute a disease. These symptoms 

 may occur when a tumor develops in the gland, and will be inten- 

 sified if, when the tumor is removed, much of the gland substance 

 is destroyed. 



But the most important disease of the gland itself, which is 

 insidious, chronic, and progressive, is myxoedema. This affection 

 is a chronic inflammation of the thyroid gland, by which the 

 secreting structure is gradually destroyed, and which consequent- 

 ly deprives the patient of the good services which are rendered 

 by a normal gland. In many respects myxa^dema resembles 

 Bright's disease, and it was some time after the first description 

 of it by Sir William Gull before it became established that the 

 affection depended upon the impairment of function of the thy- 

 roid gland, and not upon disease of the kidney. The most promi- 

 nent symptom of the disease, and the one from which the name is 

 in part derived, is an (jedema or swelling, which, unlike the oedema 

 of Bright's disease, does not pit on pressure. This oedema is most 

 prominent in the face, and it is there that it begins, although 

 later in the disease it may extend to the hands and feet, and 

 thereby increase the general weight of the body. The lips are 

 thickened, the nose becomes large and flat, and the eyelids are 

 swollen. Owing to the swelling of the tongue and throat, the 

 character of the voice may be changed. The skin is dry, rough, 

 and peculiarly pale ; the hair falls out a symptom particularly 

 noticeable in the eyebrows the teeth become poor and the nails 

 brittle. The pulse is slow, the heart is weak, and the temperature 

 is almost always below the normal. Neuralgic pains are of com- 

 mon occurrence in myxoedematous patients, and cold weather is 

 very disagreeable to them, probably on account of their low body 

 temperature. The muscles are weak, especially those of the head 

 and neck, and all muscular movements are slowly performed. 

 The mind becomes dull and apathetic ; there is usually developed 

 irritability of temper. Hallucinations or perverted sense percep- 

 tions are not at all uncommon, and occasionally the affection 

 terminates in insanity. These patients are peculiarly sensitive 



