THE KIDNEYS. 11 



The arteries, accompanied by corresponding veins, and by 

 nerves and absorbent vessels, after ramifying in the fissure of the 

 kidney, proceed into its substance, and continue their arborescent 

 ramifications until they have arrived very near the exterior sur- 

 face. They are so uniformly distributed to the different parts of 

 the organ, that when the blood-vessels are injected with wax, 

 and the substance of the kidney is removed from the injected 

 matter, as is the case in corroded preparations, the injection 

 exhibits accurately the form of the kidney. 



The large branches of the blood-vessels occupy the vacuities 

 between the papilla in the fissure of the kidney. When they 

 penetrate the substance of the kidney, they are enclosed by 

 sheaths which are derived from the coat of the gland, and are 

 surrounded by membrane which frequently contains adeps. 



There are commonly ten or twelve papilla? in the fissure of 

 each kidney, but there are sometimes more and sometimes less 

 than this number. These papillae are surrounded by a mem- 

 branous sac of a corresponding form ; the papilla? being a cone, 

 and the sac resembling the upper part of a funnel. The sac is 

 therefore called an infundibulum. Sometimes there are two 

 papilla? in each infundibulum, and then the form of the sac is 

 not so regular. The infundibulum adheres to the base of the 

 papillae, but lies loose about the other parts of it. Each infun- 

 dibulum communicates at its apex with the pelvis of the kidney. 



The Pelvis, as has been already mentioned, is a membranous 

 sac which terminates in the ureter, exterior to the kidney. 

 This sac generally divides itself, in the fissure of the kidney, 

 into three large irregular branches, called calices, above described, 

 each of which very soon terminates in three or four of the 

 infundibula.* That portion of the sac which terminates in the 

 ureter is exterior to the kidney. 



When the interior parts of the kidney are exposed to view, 

 by the section above mentioned after the arteries and veins 

 have been minutely injected, the cortical part will be found to 



* It is more usual now with anatomists to apply the term calyx, to the cup- 

 like portion of mucous membrane which surrounds the papillae, and that of in- 

 fundibulum, to the three outlets by which the ten or twelve calices discharge 

 into the common cavity of the pelvis of the kidney. p. 



VOL. II. 11 



