THE URIXE THE SUPRARENAL BODIES. 939 



must be considered approximative only, since the proportion of the ingredients is 

 liable to great variation in dependence upon food, exercise, and other conditions : 

 Urea ........ 49'68 



Uric acid ........ 1-61 



Extractive matters, ammoniacal salts, and chloride of sodium . 28 '9 5 



Alkaline sulphates . ...... 11-58 



Alkaline phosphates . . . . . . 5 - 96 



Phosphates of lime and magnesia . . . 1-50 



99-28 

 Among the extractive matters are kreatine, kreatinine, and hippuric acid. 



SUPRARENAL BODIES. 



The suprarenal bodies or 'capsules, or suprarenal glands, (capsulae atrabi- 

 larise sen renes suecenturiati of old anatomists), are two flattened bodies, 

 each of which has a somewhat crescentic or bent triangular shape, and sur- 

 mounts the corresponding kidney. The upper border, convex and thin, is 

 often considerably elevated in the middle so as to form two sides of a tri- 

 angle. The lower border is concave, and rests upon the anterior and inner 

 part of the summit of the kidney, to which it is connected by loose areolar 

 tissue : it is thick, and almost always deeply grooved. The posterior sur- 

 face rests upon the diaphragm. Its anterior surface is covered on the right 

 side by the liver, and on the left by the pancreas and spleen : it presents an 

 irregular fissure named the hilus, from which the suprarenal vein emerges. 

 The right capsule, like the right kidney, is placed lower down than the left. 



The suprarenal capsules vary in size in different individuals, and the left is 

 usually somewhat narrower at its base, but longer from above downwards, 

 and larger than the right. They measure from an inch and a quarter 

 to an inch and three-quarters in height, and about an inch and a quarter in 

 width ; their thickness is from two to three lines. The weight of each in the 

 adult is from one to two drachms. 



Besides a covering of areolar tissue mixed frequently with much fat, the 

 suprarenal capsules have a thin fibrous investment. Externally, they have 

 a yellowish or brownish-yellow colour. When divided, they are seen to 

 consist of two substances : one, external or cortical, is of a deep yellow 

 colour, firm and striated, and forms the principal mass of the organ ; the 

 other, internal or medullary, is in the adult of a dark brownish-black hue, 

 and so soft and pulpy that some anatomists have erroneously described a 

 cavity within it. 



The fibrous investment is so intimately connected with the deeper parts 

 that it cannot be removed without lacerating the subjacent structure. Its 

 deeper layers are destitute of elastic fibres, and are particularly rich in 

 nuclei : they are continuous with the septa which enter into the formation 

 of the substance of the organ. 



The cortical part of the suprarenal body, examined with a low magni- 

 fying power, is seen to consist of stroma, in which are imbedded columnar 

 and reticulated masses measuring on an average ^th of an inch in 

 diameter, arranged vertically to the surface of the organ, and containing 

 cellular constituents. In the deepest part of the cortex, however, the 

 colour is darker, and the columnar arrangement is lost, the stroma being 

 more equally scattered ; and immediately beneath the fibrous coat there is 

 another very narrow layer in which the stroma forms oval spaces, of which 

 it is difficult to say whether they communicate with the extremities of the 

 columns or not. These inner and outer layers have been named by J. Arnold 

 respectively zona reticularis and zona glomerulosa, while he applies the term 



