270 C. N. H. LONG 



such a manner that their secretions are brought into operation in a way 

 best adapted to the needs of the moment and with consequences that 

 result in the preservation of the internal environment within certain 

 narrow hmits. In this regard the adrenal cortex is of particular perti- 

 nence, although it is not the only endocrine gland concerned in the 

 regulation of metabolism. 



I have been asked to write particularly on the work of my colleagues 

 and myself on the function of the adrenal cortex.^ What we have done 

 represents only a small part of the many contributions that have been 

 made to this subject in recent years. Though it is quite impossible to 

 mention even briefly all these contributions, anything we have done has 

 been immeasurably helped by the work of our predecessors and con- 

 temporaries. 



There are two further points I should mention in this general intro- 

 duction to the subject. The first is that, unknown to Montesquieu and 

 the French Academy, the adrenal glands really compose two endocrine 

 organs, the adrenal medulla and adrenal cortex. This paper is concerned 

 largely with the function of the latter, but it should be emphasized that 

 the methods used and the general hypotheses stated are common to a 

 study of any of the ductless glands. Furthermore the work done on the 

 adrenal cortex has revealed as clearly as in the case of any other gland 

 the integrative nature of the endocrine system. 



The investigation of the function of any endocrine gland proceeds 

 along three main lines. These are (a) the chemical nature of its hormone 

 or hormones, (b) the factors that regulate the secretion of hormones 

 by the gland, and (c) the mode of action of the hormone or the manner 

 in which it produces the observed changes in the chemical processes 

 and consequently the degree of activity of the cells upon which it acts. 



For my part I have nothing to report regarding the first of these 

 lines of investigation, but I cannot pass unnoticed the brilliant achieve- 

 ments of recent years that have led first to the isolation and more re- 

 cently to the synthesis of the hormones of the adrenal cortex. For it 

 must be remembered that the isolation in pure form of a hormone is 

 not only an achievement in itself, but makes immeasurably easier the 

 work of those who are investigating the function of the gland from 

 which it comes. 



2 The experiments that are referred to in this paper were carried out in association 

 with Dr. A. White, Dr. and Mrs. G. Sayers, Miss E. Fry of the Department of Physio- 

 logical Chemistry, and Dr. T. Dougherty of the Department of Anatomy, Yale Univer- 

 sity. 



