484 CHEMICAL PATHOLOGY OF THE DUCTLESS GLANDS 



maturity. 1 In adult animals, besides decreased metabolism 

 there occur also various trophic changes in the skin and its 

 appendages, an increased amount of mucin-like material in the 

 tissues, and greatly decreased nervous and mental activity. 

 All these conditions are relieved to greater or less degree by 

 administration of thyroid tissue or its preparations. Evidently, 

 therefore, the thyroid exerts an influence upon growth and tis- 

 sue changes ; whether this depends upon its influence upon 

 metabolism, or is an independent and specific function, cannot 

 be determined. 



How the thyroid or its secretion modifies metabolism is not 

 yet understood. One is reminded of the effects of kinases upon 

 enzymes and their antecedents, and it may be imagined that the 

 thyroid secretion activates both proteolytic and oxidative 

 enzymes within the cells. Shryver, 2 indeed, did find that 

 administration of thyroid to dogs for some time before killing 

 them causes their liver tissue to undergo autolysis more rapidly 

 than normal, although Wells 3 had been unable to observe 

 any increased amount of autolysis when thyroid extracts acted 

 upon liver tissue in vitro. 



Detoxicatory Function. The evidence that the thyroid 

 has for its function the destruction or neutralization of poisonous 

 substances formed in metabolism or through intestinal putrefac- 

 tion is as follows : 



(1) After total removal of the thyroid from many species of 

 animals acute symptoms develop that suggest strongly an intox- 

 ication ; often a typical tetany develops, resembling the tetany 

 that is associated with gastric dilatation, 4 and which, as pre- 

 viously mentioned, is believed to be due to toxic products of 

 gastric putrefaction and fermentation. 



(2) After removal of the thyroid, marked changes occur in the 

 blood, there being a severe anemia (as low as 2,000,000 red cor- 

 puscles), with some leucocytosis, and there occur structural 

 changes in the blood-vessel walls (Kishi 5 ). Cytoplasmic degen- 

 eration of the liver, kidneys, and myocardium may also result 

 (Bensen 6 ). These effects suggest strongly the presence of 

 poisonous substances in the blood of persons or animals lacking 

 sufficient thyroid tissue. 



1 Literature concerning effect of thyroidectomy upon generative functions 

 riven by Caro, Berl. klin. Woch., 1905 (42), 310 ; and Lanz, Beitr. klin. Chir., 

 1905 (45), 208. 



2 Jour, of Physiol, 1905 (32), 159. 



3 Amer. Jour. Physiol., 1904 (11), 351. 



4 See Pineles, Deut. Arch. klin. Med., 1906 (85), 491. 



5 Virchow's Arch., 1904 (176), 260. 



6 Virchow's Arch., 1902 (170), 229. 



