URINARY SYSTEM. 275 



a layer of soft yellow fat), is partially divided into two un- 

 equal lobes by a fissure running directly across from the notch 

 towards the circumference: in many subjects the upper division 

 is in part subdivided by a smaller fissure, which also proceeds 

 transversely from the notch, into two portions : still it is one 

 continuous or conglobate body, which is not the case in bears 

 and in the cat tribe, where these lobes, being perfectly distinct, 

 constitute it a conglomerate gland. The under surface has like- 

 wise a middle transverse fissure, but it is less in extent ; some- 

 times we find two or three others, but small and unworthy of 

 notice. This is the part bedded in adipose matter : the quan- 

 tity of adeps, however, though considerable in very fat subjects, 

 is inferior to what is found in the herbivorous ruminant, in whom 

 it concretes after death into a remarkably white, firm mass, well 

 known by the name of suet. Now, that the gland is inverted, 

 the notch is brought more into view : in some subjects this forms 

 a considerable breach in the body of the gland, in others it 

 makes only a part of the transverse fissure aforementioned : it 

 is designed, like the porta of the liver, to give ingress to the 

 bloodvessels and egress to the duct belonging to the gland. — 

 The border, thick and rounded, narrows and describes the seg- 

 ment of a circle anteriorly ; broadens and extends into a larger 

 arc posteriorly : by adverting to this circumstance, and attending 

 to the distinguishing characters of the surfaces, the kidney of 

 one side may be known from that of the other, although both 

 should have been removed from the body. 



Capsule. — The kidney has a capsule of its own, every where 

 adherent to its surfaces through the intervention of a very deli- 

 cate cellular tissue, which tissue may be traced in places into the 

 glandular substance itself: at the notch also processes leave the 

 capsule to accompany the renal vessels and nerves throughout their 

 ramification, and serve at once as an additional tunic to them, 

 and a suitable connecting medium between them and other 

 parts. 



Structure. — The interior substance of the kidney is most 

 broadly exposed to view by carrying a horizontal section through 

 its middle in the line of its long axis. The surface exposed by 

 this section exhibits two distinct shades of colour, united by a 

 broad intervening circle of dark red : the outer part has a 

 brownish red tint, and is denominated the cortical substance, 

 because it surrounds the medullary or tubular substance, as it is 

 called, which has a carnation hue, growing lighter as it extends 

 inward. These substances not only differ in hue ; they differ in 

 consistence, in disposition, and in structure. The cortical part 

 possesses a uniformity of aspect something like that of the liver, 



