THE SUPRARENAL GLANDS. 217 



resemble the nerve-cells of the central organs, although they 

 cannot definitively be declared to be such. 



§ 194. 



Vessels and nerves. — The blood-vessels of the suprarenal 

 glands are numerous, lie in the stroma of connective tissue, 

 and form two kinds of capillary plexuses ; one in the cortex with 

 elongated meshes, and one in the medullary substance with 

 more rounded interstices. The arteries arise as numerous 

 (amounting to twenty) small vessels from the neighbouring larger 

 trunks (phrenic, cseliac, aortic, renal) and either penetrate directly 

 into the medullary substance or ramify in the cortical. The 

 latter, which are the more numerous, cover the outer surface of 

 the organ with their multiplied ramifications, and form a wide 

 capillary plexus even in the outer tunic. They then subdivide 

 into numerous fine twigs, and dip down into the dissepiments 

 of the cortex, in which, becoming more and more attenuated, 

 they run straight towards the medulla, being mutually con- 

 nected in their course by pretty numerous transverse anasto- 

 moses, so that the cortical cylinders are surrounded by blood 

 on all sides. The extremities of these vessels extend to the 

 interior of the medulla, where, in common with the arteries 

 which penetrate directly to the same point (of which, how- 

 ever, according to Nagel, in the Sheep, some proceed from the 

 medulla entirely to the cortex) they form a rich capillary plexus 

 of rather large vessels. The veins arise chiefly from this 

 latter plexus, and, within the medullary substance, join the 

 principal vein of the organ, — the v. suprarenalis — which 

 comes out on the anterior surface, at the so-termed hilus, 

 emptying itself, on the right side, into the vena cava and on the 

 left, into the renal vein. Besides these, a good many smaller 

 veins arise from the cortex, which either accompany the 

 arteries in pairs, or proceed independently and open into the 

 renal and phrenic veins, and into the inferior vena cava. Of 

 lymphatics, I have as yet noticed only a few small trunks on 

 the surface of the organ, but none in the interior or coming 

 out from it. The nerves of the suprarenal glands are, as was 

 correctly stated by Bergmann, extremely numerous, arising 

 from the semilunar ganglion and the renal plexus ; according 

 to Bergmann also, to a small extent, from the vagus and 



