150 PRACTICAL MICROSCOPY. 



THE SUPRARENAL CAPSULE. 



These bodies are attached by areolar tissue to the summit of the 

 kidneys, and consist of several folia or leaflets. An examination of 

 one of these leayes will give us an idea of the organ as a whole. The 

 plan of structure seems to be as follows: 



In the connective tissue which supports the folia are found arterial 

 branches derived from the phrenic (and sometimes from the renal 

 before it enters the kidney). These arteries penetrate the organ, 

 break up immediately into capillaries, which finally converge toward 

 the centre of the leaflet; the blood is here collected in thin-walled 

 veins, by which it is drained into the suprarenal vein, thus leaving 

 the capsule. 



The capillary meshes vary in form and size, according to their 

 position. Near the circumference of the leaves the meshes are small 

 and ovoid, while, as the centre is approached, they become elongated. 

 These spaces between the capillaries are filled with compressed, glob- 

 ular, nucleated cells, the smaller containing only perhaps six or 

 eight, while the longer may be occupied by thirty or forty of these 

 cell elements, which constitute the parenchyma of the organ. This 

 variation in size of the cell compartments, contributing, as it does, 

 to alter the appearance of the different zones of the tissue, has given 

 rise to a division into cortex and medulla, with subdivisions even of 

 these. There is no histological or physiological difference, as we 

 believe, between the different parts of the folia of the suprarenal cap- 

 sule, except as has been indicated. The structure is exceedingly 

 simple, although its function is not settled beyond question. 



PKACTICAL DEMONSTKATION. 



The tissue is best hardened in strong alcohol, and should be cut 

 as soon as the hardening is complete. It will be sufficiently firm to- 

 ad mi t of the thinnest sections being made free-hand or with a simple 

 microtome. The cuts, stained with haoma. and eosin, give excellent 

 differentiation. 



