THE SUPRA-RENAL GLANDS. 



593 



Fig. 420. 



Portion of a vertical section through 

 the cortex of the supra-renal body in 

 man. a. Septa of connective tissue. 6. 

 Cortical cylinder whose composition 

 from cells is more or less distinctly 

 manifest. (Magnified 300 diameters.) 



longed from the cortical lamellae, and pervading the whole interior, 

 forming a network with rather wide meshes. This is filled by a 

 pale, finely granular substance, contain- 

 ing pale cells, T ^J^ to ^-f of an inch in 

 diameter, resembling the nerve-cells of 

 the central organs, though they cannot 

 be definitely declared to be such. (Kol- 

 liker.) 



The bloodvessels of the supra-renal 

 glands are very numerous. Some- 

 times even twenty arterial trunks enter 

 one of these glands. A capillary plexus 

 with elongated meshes exists in the 

 cortical substance, and one with round- 

 ed interstices in the medullary. Thus 

 the cortical cylinders are surrounded 

 by blood on all sides ; ajid this capil- 

 lary plexus joins that of the medul- 

 lary substance, formed, principally by arteries penetrating at once 

 into the latter. A few lymphatics are found on the surface of the 

 organ, but more in its interior. 



The nerves of the supra-renal glands are very numerous; being 

 derived from the semi-lunar ganglion, and the renal plexus; and 

 also, to a small extent, from the pneumogastric and the diaphragm- 

 atic. (Bergmann). Kolliker has counted 33 trunks entering the right 

 supra-renal gland, varying from ^'to gj^ of an inch in diameter; 

 and found that almost without exception, they were constituted of 

 dark-bordered, finer, and medium-sized, or even thick, nerve-fibres; 

 and were furnished with isolated larger or smaller ganglia. They 

 appear to be all destined for the medullary substance, where there 

 is an extremely rich nervous plexus; the terminations of the fibres 

 being, however, nowhere perceptible. 



The supra-renal glands are developed simultaneously with the 

 kidneys, but independently of them ; and are originally larger than 

 they. The first appearance and growth of the blastema where they 

 are found is unknown. 



Of the function of the supra-renal glands, nothing positive is 

 known. They, however, have pretty certainly no physiological 

 connection with the kidneys. Kolliker thinks that while the cor- 

 tical portion may belong to the class of blood- vascular glands, the 

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