484 KIDNEY. [CHAP, xxxiv. 



only 14*39 per cent, of solid matter was present, so that in this 

 instance the increased weight of the organ was undoubtedly due 

 to a larger proportion of water than occurs in health,, rather than 

 to the deposition of any adventitious tissue, or to an increase of the 

 normal gland-textures. 



Surface of the Kidney. The kidney is immediately invested with 

 a firm fibrous coat, called the capsule, which is composed of con- 

 densed areolar tissue, and is continuous with the tissue consti- 

 tuting the matrix of the kidney, in the meshes of which the tubes 

 ramify : some small vessels also connect the capsule of the kidney 

 with the proper gland-structure. At the hilum, the capsule is con- 

 tinuous with the external or fibrous coat of the pelvis of the 

 kidney and the fibrous coat of the ureter. The vessels also receive 

 an investment from it at this point. 



If the surface of the kidney be carefully examined, it is seen to 

 be imperfectly mapped out into a number of small polyhedral spaces 

 or lobules, in general appearance somewhat resembling the markings 

 of the lobules of the liver. These markings are in part due to the 

 arrangement of small branches of the veins which are spoken of, by 

 anatomists, as the stellate veins. Commencing at the surface of 

 the kidney, they penetrate the cortical part in a vertical direction, 

 at nearly equal distances, and receive, in their course to the hilum, 

 the blood from the venous plexuses surrounding the secreting 

 tubes. In the spaces just described, may be seen the convolu- 

 tions of some of the uriniferous tubes. No arteries reach the 

 surface. 



Ferrein supposed that the tubes formed little pyramids, each of 

 which radiated from the medullary towards the cortical part of the 

 kidney, the base of each pyramid consisting of one of these spaces 

 or lobules. It appears, however, that although each pyramid 

 contains many tortuous tubes, with their capillaries, the convolu- 

 tions of a single tube are by no means confined to one pyramidal 

 space. 



Besides the apparent divisions into lobules just referred to, the 

 surface of the kidney bears the vestiges of several fissures, marking 

 it out into lobes which may be seven or eight or more in number ; 

 these lobes indicate the original condition of the kidney in 

 intra-uterine life when they were separated from each other, and 

 formed distinct renules. In the embryos of mammalia generally, 

 the same arrangement is observed ; and it remains permanent in 

 the cetacea. In the kidney of the otter, seal, ox, and some other 



