THE VISCERA. 237 



b. The tubular medullary substance, s. tubulosa, s. medullaris [the excretory 

 portion]], paler than the former, striated like muscular fibres, consists of 

 twelve to fourteen (twenty) conical lobes (pyramidcs Malpighii~), which an- 

 separated from one another by the cortical substance, and are covered by the 

 same also on the basis which is directed towards the surface of the kidney, 

 whilst the free apex terminates in the hilus like a nipple, as papilla renalis. 

 There are generally only ten to twelve papilla, because some have blended 

 together. Each Malpighian pyramid consists of several fasciculi (these are 

 pyramides Ferreinii') of parallel canaliculi, tubuli uriniferi recti s. Belliniani, 

 which open with fine orifices on the renal papillae, or rather on the walls of 

 a fossa two or three lines deep, inside the papillae, that is, ductus papillar. 

 Feri-ein. The uriniferous tubes consist of a clear structureless memb. propria, 

 and have a diameter of 0-009 to 0-016 line. 



(Renuli, s. lobi rents, is a name given to the Malpighian pyramids which in 

 early youth, in animals throughout the whole of life, are limited to the 

 surface of the kidney, so that the organ appears to consist of so many 

 small kidneys.) 



The vessels for the most part go into the cortical substance. The great 

 art. renalis divides in the hilus into two or three large branches, which again 

 divide at the boundary between the cortical and medullary substance, and 

 form a capillary network, the close meshes of which surround the basis of 

 each Malpighian pyramid, dispatch branches thence into the cortical sub- 

 stance, which divide in a forked manner, and pass along the undulating 

 tubuli into the red granules (acmi Malp.). Vena renalis passes out of the hilus 

 before the artery, and sinks into the ven. cava inferior. The vessels of one 

 lobe do not communicate with those of another. Lymphatics : numerous, on 

 the surface. Nerves: numerous, from plexus Solaris, N. splanchnicus minor. 

 From plexus renalis, plexus spermaticus passes off. 



Function of the kidneys : Secretion of the urine (in the urinary 

 canaliculi). 



471. 2. Excretory ducts of the kidneys. These are the 

 renal calyces, the pelvis renalis, and the ureters. 



a. The Calyces renales, s. infundibula, are small, membranous, sometimes 

 forked cylinders, which surround the basis of one or more renal papillae. 

 Their mucous membrane terminates blindly upon the papillae, but at the 

 same time blind processes pass into the substance of the latter, where the 

 urinary canaliculi open. (Henle.) They are surrounded by the fat of the 

 hilus, are present in indefinite number (seven to fourteen), and, arranged in 

 rows, they pass into three branches, which form again. 



b. The pelvis of the kidney, pelvis renalis. This is funnel-shaped, flat 

 from before backwards, projects out behind art. and ven. renalis from the 

 inferior extremity of the hilus, is very extensible, and contracts as it proceeds 

 into: 



c. The ureter, that is the long (ten or twelve inches) membranous tube 

 which descends on either side to the basis of the bladder. Generally of the 

 thickness of a raven's or goose's quill ; the ureter may be, with its thin 

 whitish wall, considerably distended. We find sometimes two ureters on 

 one side if the renal calyces have not united into a single pelvis. Direction : 

 obliquely downwards and inwards to the sides of the basis oss. sacri, then 



