SUPRARENAL BODIES. 665 



closely connected with the sympathetic ganglia, and usually contain numerous 

 ganglion cells distributed amongst the proper cells of the body. 



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 invested by a tunica 

 propria, 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 suprarenal bodies (Balfour, No. 292, pp. 242 244) are de- 

 veloped from the sympathetic ganglia. These ganglia, shewn in an early 

 stage in fig. 380, sy.g, become gradually divided into a ganglionic part and a 

 glandular 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, (i) 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 suprarenals of Mammalia, and (2) irregular cords, 

 in part provided with a lumen, filled with fat-like globules 1 , amongst which 

 are nuclei. On treatment with chromic acid the fat globules disappear, 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 indifferent 

 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. 953955) 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 from the mesoblast, 

 and that the glands are closely connected with sympathetic ganglia ; while 

 Kolliker also states that the posterior part of the organ is unpaired in the 

 embryo rabbit of 1 6 or 17 days. 



The structure and development of what I have called the interrenal body 



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

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



