SECRETION. 



Extirpation of the thyroid, for relief from symptoms due to grave 

 pathologic changes, has been followed in human beings by symptoms 

 similar to those of myxedema. To this condition the terms operative 

 myxedema and cachexia strumipriva have been applied. 



After the publication of the history of the myxedema which fol- 

 lowed surgical removal of the thyroid, Schiff, in 1887, repeated his 

 earlier experiments on dogs, and found again that removal of the 

 thyroid was speedily followed by tremors, convulsions, and death. 

 Similar experiments were made by Horsley on monkeys, with results 

 which resembled those characteristic of myxedema. Among the 

 symptoms which 

 developed within a 

 few days afterthe 

 removal of the gland 

 may be mentioned 

 loss of appetite ; fib- 

 rilTar contractions 

 of muscles; tremors 

 and spasms; mu- 

 cinoid degeneration 

 of the skin, giving 

 rise to puffiness of 

 the eyelids and face 

 and to a swollen 

 condition of the 

 abdomen ; hebetude 

 of mind, frequently 

 terminating in 

 idiocy ; fall of blood- 

 pressure; dyspnea; 

 albuminuria ; atro- 

 phy of the tissues, 

 followed "By ""death 

 of the animal in the 

 course of from fivejto eight weeks. The complexus of symptoms 

 observed in monkeys was~drvided by Horsley into three stages: viz., 

 the neurotic, the mucinoid, and the atrophic. 



It is evident that the presence of the thyroid is essential to 

 the normal activity of the tissues generally. As to the manner 

 in which it exerts its favorable influence, there is some difference 

 of opinion. The view that the gland removes from the blood cer- 

 tain toxic bodies, rendering them innocuous and thus preserving 

 the body from a species of auto-intoxication, is gradually yielding to 

 the more probable view that the epithelium is engaged in the secre- 

 tion of a specific material, which finds its way into the blood or lymph 



FIG. 1 88. A LOBULE FROM A THIN SECTION OF THE 

 THYROID GLAND OF AN ADULT MAN. i. Colloid 

 substance. 2. Epithelium. 3. Tangential section 

 of a tubule, the epithelium viewed from the surface. 

 4. Tubule in transverse section. 5. Connective tissue. 

 (Stohr.) 



