134 INTERNAL SECRETION 



termed "accessory interrenal bodies r> (Beizwischennieren), may 

 be formed primarily by the persistence and after-growth of isolated 

 interrenal buds placed in a caudal direction ; they may also be 

 formed secondarily by fission of the principal organ, due either to 

 interproliferation of the sympathetic elements, or to circumscrip- 

 tion of growth and consequent division as trie-result of connective 

 tissue formations. 



It is obvious that wherever, in the course of embryonal 

 development, portions of the interrenal and adrenal systems come 

 into close topographical relationship, true "accessory suprarenals" 

 (Beinebennieren) may be formed ; that is to say, organs composed 

 of a cortex and medulla with a structure the exact counterpart of 

 that of the suprarenals. The accounts of such bodies are, how- 

 ever, very scanty. In 1884, d'Ajutolo found a true accessory 

 suprarenal in the plexus pampiniformis of a newly-born boy; and 

 Delamare found one in 1904, in the solar plexus. Aschoff (1903) 

 describes chromaffine bodies and interrenal structures lying side 

 by side in the paradidymis and parovarium of newly-born children. 



Comparative embryology supplies etiological proof of the 

 existence within the. body of animals of two independent supra- 

 renal systems ; it also shows how, in the course of philogeny, these 

 systems tend to an increasing and more perfect unification. The 

 question arises as to whether this coalescence results in an organ 

 the homogeneous character of which is purely morphological, or 

 whether this combination of the two heterogeneous systems is the 

 expression of an intimate functional relationship of the two, the 

 suprarenal being perhaps functionally a higher organic entity. 



But physiology, whose province it is to solve this problem, 

 was from the beginning confronted with an anatomically homo- 

 geneous suprarenal and, up to the present, has occupied itself 

 solely with the suprarenal function. 



The following tables illustrate the suprarenal systems as 

 they occur in all the animal classes. Table A shows all that is 

 at present known concerning the invertebrate animals and the 

 vertebrates up as far as the bactrians inclusive. In addition to 

 the permanent conditions affecting the interrenal system, it shows 

 those which obtain in the embryonal interrenal. Table B includes 

 all vertebrates higher than the bactrians ; it illustrates the condi- 

 tions which govern the embryonal interrenal, those affecting the 

 free portions of both the interrenal and adrenal systems, and the 

 conditions governing those portions of both systems which unite 

 to form true accessory suprarenals. 



PHYSIOLOGY OF THE SUPRARENALS. 



EXPERIMENTAL EXTIRPATION. 



It has already been pointed out that Addison's epoch-making 

 discovery of the results which, in man, arise from the suppression 





