DUCTLESS GLANDS. 353 



Vessels and Nerves. The blood-vessels going to the supra- 

 renal capsules are very numerous, and are derived from the 

 aorta, the phrenic, the coeliac axis, and the renal artery. Some- 

 times as many as twenty distinct vessels penetrate the capsule. 

 In the cortical substance the capillaries are arranged in elon- 

 gated meshes, anastomosing freely, and surrounding the 

 tubes, but never penetrating them. In the medullary sub- 

 stance the meshes are more rounded, and here the vessels 

 form a very rich capillary plexus. Two large veins pass 

 out, to empty, on the right side, into the vena cava, and on 

 the left into the renal vein. Other smaller veins empty into 

 the cava, the renal, and the phrenic veins. 



The nerves are very numerous, and are derived from the 

 semilunar ganglia, the renal plexus, the pneumogastric, and 

 the phrenic. Kolliker mentions that he has counted, in the 

 human subject, thirty-three nervous trunks entering the 

 right suprarenal capsule. 1 According to Grandry, the nerves 

 pass directly to the medullary substance, but here their mode 

 of distribution is unknown. In the medullary matter, how- 

 ever, are two ganglia, characterized by nerve-cells of the or- 

 dinary form, and situated close to the central vein. 3 



Nothing whatever is known of the lymphatics of the 

 suprarenal capsules, and the existence of these vessels, even, 

 is doubtful. 



Chemical Reactions of the Suprarenal Capsules. A few 

 years ago M. Yulpian discovered in the medullary portion 

 of the suprarenal capsules a peculiar substance, soluble in 

 water and in alcohol, which gave a greenish reaction with 

 the salts of iron and a peculiar rose-tint on the addition of 

 iodine. He could not determine the same reaction with ex- 

 tracts from any other parts. 3 Later, in conjunction with M. 



1 KOLLIKER, Handbuch der Gewebelehre, Leipzig, 1867, S. 620. 



2 Op. cit., p. 400. 



* VULPIAN, Note sur quelques reactions propres d la substance des corps surre- 

 nates. Comptes rendus, Paris, 1856, tome xliii., p. 663. 

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