420 



USES OF THE LIVER DUCTLESS GLANDS. 



cells or of columns of cells surrounded by delicate, fibrous trabeculae. On 

 making thin sections through the cortical substance previously hardened in 

 chromic acid and rendered clear by glycerine, rows of cells are seen, arranged 

 with great regularity, and extending, apparently, from the investing mem- 

 brane to the medullary substance. The cells appear to be enclosed in tubes 

 measuring y^Vff to ^-5- of an inch (25 to 80 p.) in diameter. They are gran- 

 ular, with a distinct nucleus and nucleolus and a variable number of oil- 

 globules. They measure -pfVo to T ^Vr ^ an i ncn (14 to 25 //.) in diameter. 

 Between the rows of cells of the cortical substance, are bands of fibrous tissue 

 connected with the investing membrane of the capsule. 



Medullary Substance. The medullary substance is much paler and more 

 transparent than the cortex. In its centre are openings which mark 

 the passage of its venous sinuses. It is penetrated in every direction by vcrv 

 delicate bands of fibrous tissue, which enclose blood-vessels, nerves, and elon- 

 gated, closed vesicles containing cells, nuclei and granular matter. These 

 vesicles, which are -g s of an inch (0'32 mm.) long and about -^fa of an inch 

 (64 /A) broad, have been demonstrated in the ox and in the human subject. 

 The cells in the human subject are Y^ to y^^ of an inch (15 to 20 //,) in 

 diameter. They are isolated with difficulty and are very irregular in their 



form. The nuqlei measure about ^Vrr f 

 an inch (10 ju,). The medullary substance is 

 c peculiarly rich in vessels and nerves. 



Vessels and Nerves. The blood-vessels 

 going to the suprarenal capsules are very 

 abundant and are derived from the aorta, 

 the phrenic artery, the coeliac axis and the 

 renal artery. Sometimes as many as twenty 

 distinct vessels penetrate each capsule. In 

 the cortical substance the capillaries are ar- 

 ranged in elongated 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 vena cava, the renal 

 and the phrenic veins. 



The nerves are very abundant and are 

 derived from the semilunar ganglia, the re- 

 nal plexus, the pneumogastric and the phren- 

 ic. Kolliker counted in the human subject 

 thirty-three nervous trunks entering the 

 right suprarenal capsule. The nerves prob- 

 ably pass directly to the medullary substance, but here their mode of distri- 





FIG. 140. Section of a human suprarenal 

 capsule (Cadiat). 



A, fibrous coat; B, cells of the cortical sub- 

 stance, arranged in rows ; c, vesicles of 

 the medullary substance ; D, blood-ves- 

 sels. 



