548 SUPRARENAL BODIES. 



both of these structures probably unite in the higher types to form the 

 suprarenal bodies. 



One of them consists of a series of paired bodies, situated on the 

 branches of the dorsal aorta, segmentally arranged, and forming a chain 

 extending from close behind the heart to the hinder ejid of the body cavity. 

 Each body is formed of a series of lobes, and exhibits a well-marked 

 distinction into a cortical layer of columnar cells, and a medullary sub- 

 stance formed of irregular polygonal cells. As first shewn by Leydig, they 

 are closely connected with the sympathetic ganglia, and usually contain 

 numerous ganglion cells distributed amongst the proper cells of the l)ody. 



The second body consists of an unpaired column of cells placed between 

 the dorsal aorta and unpaired caudal vein, and bounded on each side by 

 the posterior parts of the kidney. I propose to call it the interrenal 

 body. In front it overlaps the paired suprarenal bodies, but does not 

 unite with them. It is formed of a series of well-marked lobules, etc. In 

 the fresh state Leydig (No. 506) finds that "fat molecules form the chief 

 mass of the body, and one finds freely imbedded in them clear vesicular 

 nuclei." As may easily be made out from hardened specimens it is in- 

 vested by a tunica pi-opria, which gives off septa dividing it into well- 

 marked areas filled with polygonal cells. These cells constitute the true 

 parenchyma of the body. By the ordinary methods of hardening, the oil 

 globules, with which they are filled in the fresh state, completely disappear. 



The paired siiprarenal bodies (Balfour, No. 292, pp. 242 — 244) are de- 

 veloped troin the sympathetic ganglia. These ganglia, shewn in an early stage 

 in tig. 380 sy.g, become gradually divided into a ganglionic part and a glandvilar 

 part. The former constitutes the sympathetic ganglia of the adult ; the latter 

 the true paired suprarenal bodies. The interrenal body is however 

 developed (Balfour, No. 292, pp. 245 — 247) from indifferent mesoblast cells 

 between the two kidneys, in the same situation as in the adult. 



The development of the suprarenal bodies in the Amniota has been 

 most fully studied by Braun (No. 503) in the Reptilia. 



In Lacertilia they consist of a pair of elongated yellowish bodies, 

 placed between the vena renalis revehens and the generative glands. 



They are formed of two constituents, viz. (1) masses of brown cells 

 placed on the dorsal side of the organ, which stain deeply with chromic acid, 

 like certain of the cells of the siiprarenals of Mammalia, and (2) irregular 

 cords, in part provided with a lumen, filled with fat-like globules ', amongst 

 which are nuclei. On treatment with chromic acid the fat globules dis- 

 appear, and the cords break up into bodies resembling columnar cells. 



The dorsal masses of brown cells are developed from the sympathetic 

 ganglia in the same way as the paired suprarenal bodies of the Elasmo- 

 branchii, while the cords filled with fat-like globules are formed of in- 

 different mesoblast cells as a thickening in the lateral walls of the inferior 

 vena cava, and the cardinal veins continuous with it. The observations of 

 Brunn (No. 504) on the Chick, and Kolliker (No. 298, pp. 953 — 955) on the 

 Mammal, add but little to those of Braun. They shew that the greater 

 part of the gland (the cortical substance) in these two types is derived fiom 

 the mesoblast, and that the glands are closely connected with sympathetic 



^ These globules are not formed of a true fatty substance, and this is also probably 

 true for the similar globules of the interreual bodies of Elasmobranchii. 



