DEVELOPMENT OF SUPRARENAL BODIES IN MAMMALIA. 23 



large ganglion on one side of the section, and I am almost 

 certain that it becomes continuous with irregular cords, con- 

 tinuous in their turn with the medulla. In many places, 

 as h, these cords taper and seem to pass off into fibres, which 

 are certainly like nerve fibres, and at others, as y, nerves 

 pass into cell masses, and are lost among them. 



Taking these facts in connection with the developmental 

 history of the medulla, it seems to me almost certain that 

 the process of medullary substance emerging at the outer 

 surface of the suprarenal at its posterior end becomes in 

 some way intimately connected with nerves and ganglion 

 cells. I may remark that Braun (loc. cit.) finds ganglia at 

 the anterior and posterior terminations of the suprarenals in 

 the Reptiles, and that the medullary cells are in intimate 

 connection with them. My researches appear to show that 

 the same arrangement obtains in the rabbit at the posterior 

 end. 



In the human suprarenals, according to 'Quain's Anatomy,' 

 the arteries are derived from the aorta, the phrenic and the 

 renal arteries. Brunn (loc. cit.) remarks that many arteries 

 entering the connective-tissue capsule divide themselves in 

 it into numerous fine branches ; some of these go directly 

 through the cortical substance to the medulla, but by far 

 the majority form a close anastomosis in the capsule, and 

 enter the suprarenal with larger process of connective tissue. 

 The fine network of capillaries in the cortical and medullary 

 part has already been mentioned. In regard to nerves, I 

 am only certain of the existence of one in the rabbit arising 

 from the sympathetic cords far in front in the dorsal region, 

 and entering the suprarenal just within its posterior half. 

 In ' Quain's Anatomy ' nerves are stated to be derived from 

 the solar plexus of the sympathetic and from the renal 

 plexuses, and to be exceedingly numerous. 



Development of the Suprarenal Bodies. — According to 

 Kolliker,^ the suprarenal bodies in the rabbit appear first 

 on the twelfth or thirteenth day of gestation as masses of 

 somewhat large round cells on each side of, and ventral to/ 

 the aorta, on the inner side of the Wolffian bodies, and 

 dorsal to the mesentery. 



In one series of my sections of a twelve-day embryo several, 

 that pass through what must become the front part of the 

 future abdomen, show, at the spot designated by Kolliker, a 

 mass of cells (5. r., fig. 3) with large nuclei, stained with haema- 

 toxylin slightly darker than those of the surrounding cells. 

 Dorsally this mass is tolerably distinctly separated off from 



' Entwicklungsgescb. des Menschen unci der Hoheren Thiere,* p. 954. 



