KIDNEYS. 



of a conical mass, whose base looks towards the circumference 

 of the kidney, and is, together with the sides, as it were, imbed- 

 ded in the cortical part of the kidney. The conical masses are 

 usually more numerous than the calyces, in which they terminate. 

 Each is composed of minute tubes, one end of which opens on 

 the surface of the papilla, and, therefore, pours its contents into 

 the investing calyx, while the other, prolonged to the base of the 

 cone, is there continuous with the capillary termination of the ar- 

 teries, from which it receives the urine the moment it is separat- 

 ed from the blood. It passes successively by the tubuli, calyces, 

 smaller tubes or infundibula, and pelvis ; whence it enters the 

 ureter, and is conveyed to the bladder. 



The pelvis is covered by a mucous membrane, which, doubt- 

 less, lines also the tubuli uriniferi to their minutest termination. 

 It is probable also that the fibrous investment of the infundibu- 

 lum and calyx is prolonged so as to become continuous with the 

 fibres which constitute the tubuli. 



From the preceding description it is obvious that the cortical 

 part of the kidney is little else than a congeries of vessels and 

 nerves connected together by cellular tissue. It is in this part 

 that the urine is separated from the blood. The medullary por- 

 tion consists of a congeries of tubes, also connected by cellular 

 tissue, through which the urine is conveyed to the pelvis of the 

 organ, whence it passes by the ureters into the bladder. It fol- 

 lows from this complicated structure that little light is likely to 

 be thrown upon the nature of these organs by subjecting them to 

 a chemical analysis. It would be impossible to separate the dif- 

 ferent kinds of vessels from each other, in order to examine them 

 separately, and scarcely less difficult to free them from the liquids 

 with which they are filled in the living animal. 



Berzelius removed the serous membrane which covered the 

 kidneys of a horse, cut the kidney itself into small pieces, and 

 suspended them in cold water till they ceased to colour that li- 

 quid,. He then pur the kidney into a porcelain mortar, and 

 pounded it with a wooden pestle. By this process it was 

 almost -all converted into a liquid, which he filtered through 

 cloth. On the cloth remained a fibrous matter, which was knead- 

 ed in water as long as it rendered that liquid milky. The fi- 

 brous matter remaining after these processes constituted an ex- 

 ceedingly small portion of the kidney employed. This solid re- 

 sidue possessed the following properties : 



