THE RELATIONS BETWEEN THE EKDOCRIN ORGANS 167 



and affords a basis for understanding the nervous manifestations found in 

 endocrin disorders and endocrin manifestations found in nervous dis- 

 orders. One cannot conceive of any marked change taking place in the 

 secretion of any of the important endocrin glands, either a withdrawal, 

 as occurs in the conditions of hypofunction, or an addition, as occurs in 

 conditions of hyperfunction, without affecting or destroying the equilib- 

 rium of the vegetative nervous system; neither can. one conceive of any 

 marked stimulation occurring in either of the divisions of the vegetative 

 system without affecting some of the endocrin glands. 



In disturbance in the vegetative nerves, the symptoms are often expres- 

 sive of stimulation of one division only, although at times there may be 

 symptoms belonging to both divisions. Endocrin disturbances are almost 

 always pluriglandular. 



With this introduction, it can be seen that the action of the vegetative 

 nerves and the secretions of the endocrin glands are so intimately related 

 and correlated that they cannot be separated. Both are avenues through 

 which action in different structures is correlated and integrated ; and each 

 in turn stimulates and receives stimulation from the other. 



The Suprarenal Glands and the Autonomic System 



Epinephrin and the Sympathetic System. The secretion of the 

 medulla of the suprarenal gland, in its relationship to the vegetative 

 nerves, is better understood than that of any other internal secretion. 

 This understanding has been facilitated by the determination of the close 

 relationship which exists between the chromaphil tissue in the medulla of 

 the suprarenal body and the cells of the sympathetic division of the vege- 

 tative nervous system, as shown by Balfour, Kohn, and Gaskell. The 

 chromaffin 3 cells found in the medulla of the suprarenal gland are differ- 

 entiated sympathetic cells, having been derived from that portion of the 

 central nervous system which migrated from the neural canal to form the 

 sympathetic system. They are influenced by the same stimuli that act 

 upon the sympathetic nerves (Elliott (6), 1912), and epinepkrin, the re- 

 sulting secretion, influences all tissues, except the sweat glands, that are 

 acted upon by the sympathetics, and produces the same effect as though 

 the sympathetic nerves themselves were stimulated. This fact was finally 

 brilliantly demonstrated by Elliott (a), in 1905, although foreshadowed 

 by the results of several other investigators. 



Pharmacodynamic Action of Epinephrin. The action of epinephrin, 

 as generally admitted, except in the case of the blood vessels, is not on the 

 central nerve cells, but in the organ or structure itself at the myoneural 



3 Chromaphil and chromaffin are used in the literature more or less interchangeably. 

 Historically, chromaphil has precedence. R. G. H. 



