382 B. F. KINGSBURY 



I turn now to those organs of man which as their comparative anat- 

 omy and embryology teach, in the course of phylogeny have given up 

 their original phj'siological duty and undergone a change of function. 

 I have primarily in mind the thyreoid, thymus gland, pineal gland, 

 pituitary body (hypophysis cerebri), the so-called glandula carotica, 

 the suprarenal, and a certain territory within the nasal cavities. Many 

 of these organs follow the gland type in their development and are pri- 

 marily connected with the place of origin by means of a duct. This 

 disappears later however so that from this time on the secretion that 

 is formed is passed directly into the surrounding lymph or blood ves- 

 sels (inner secretion), (p. 12). A typical change of function can 

 hardly be thought of; and when we ponder it and consider what 

 profound processes of change have taken place both anatomically and 

 physiologically, in the thyreoid gland, for example; or, in other words, 

 how the organ just mentioned has given up a prior clearly highly 

 specialized function in order to enter into very important physiological 

 relations to the entir-e organism, the question becomes quite pertinent, 

 I think, as to whether the unusual and frequent variations in form 

 and size, as also the very marked tendency to pathological alterations 

 of different character, are not due first of all in large measure to the 

 storm and stress period in its phylogeny. (p. 14). 



Finally, general biologists have recognized a principle of "retro- 

 gression with change of function" (cf. Needham '10, p. 253), 

 finding illustration in the plant and animal world. In the above 

 quotations the word function has been repeatedly employed. 

 It is not, however, I believe through a search for specific 'function' 

 that a clearer comprehension of the 'internally secreting glands' 

 is to be gained. While the adaptative aspects of the growth 

 pattern cannot be ignored, of course, it will be through the 

 analysis of the growth metabohsm of the entire organism and 

 the determination of the fundamental characteristics of growth 

 that there will be established a correct basis for the under- 

 standing of this group of structm-es in its morphological, physiologi- 

 cal and pathological aspects. 



In conclusion, I desire again to emphasize that it is clearly 

 due to no accident of development or chance circumstance 

 that the branchial pharynx in its regressive metamorphosis 

 gives rise to structures of such profound metabolic significance. 



