Chemico-Functional Integration 119 



cited. 



Concerning the effects of removal of the thyroid appa- 

 ratus he says : 



"The most acute symptoms are exhibited by carnivora such as 

 dogs, cats,, foxes, and wolves (Vincent), and the young of herbi- 

 vora (v. Eiselsberg, Sutherland Simpson) and are of a nervous 

 nature. . . . Some species exhibit no symptoms whatever at 

 least when the operation is performed on the adult. Horsley 

 states that this is the case with birds and rabbits; but according 

 to Gley, the latter are affected if care is taken to find and re- 

 move all four parathyroids, and Doyon and Jouty obtained typical 

 tetany in hens which had been parathyroidectomized. . . . Ac- 

 cording to Vincent and Jolly badgers are totally unaffected by 

 complete removal of both thyroids and parathyroids." 



From the anatomical characteristics of the organs, 

 and from the known effectiveness of minute portions of 

 them, such statements as the last must be taken with re- 

 serve. Although these results show by their diversity that 

 an enormous amount of study remains to be done on the 

 comparative side, they leave no question that the secretion 

 of the thyroid apparatus is important for the general 

 health and equilibrium of most animals in which it occurs. 

 The measure of this importance in the eyes of some authori- 

 ties is seen in such a statement as, "No cell anywhere in the 

 body can reach morphological perfection without thyroid 

 stimulus." 4 



The Internal Secretion of the Duodenal Mucous Membrane 



We now pass to an examination of the effects of the 

 internal secretion of the duodenal mucous membrane. This 

 particular secretion is selected for the reasons that it is, 

 according to Bayliss, one of its discoverers, "the most 

 typical of all the chemical messengers"; that it was one of 

 the first to be investigated ; and that it is one of the few 

 which have been isolated as definite substances. 



