SECT. 1 86.] STRUCTURE OF THE KIDNEY. 4O5 



account of thick bundles of vessels appearing there at regular 

 distances {arterioles and venulce rectos), and they diverge from 

 one another in all directions, so that, on a perpendicular section, 

 the pyramids (the papillae of course excepted) appear to radiate 

 into numerous small bundles or tufts — 'the pyramids of Fer- 

 ivin ' of some anatomists. Transverse sections, however, show 

 that those are nowise to be regarded as definite fasciculi; though 

 from a certain order in the arrangement of the tortuous tubules 

 into columnar masses, there is no objection to giving the special 

 name, pyramids of Ferrein, or, 'fasciculi corticales,' to the con- 

 tinuations of the indistinct bundles of straight tubules into the 

 cortex. These are |'" to 4-'" in breadth, are distributed in the 

 whole of the cortical portion, and as has been said, are very 

 incompletely defined from each other. The urinary tubules, even 

 where they leave the pyramids, have a slightly undulating course; 

 and this is still more the case farther on in the cortical substance, 

 where they are interwoven at first sight inextricably and without 

 regularity, constituting the tubuli contorti or corticales. These 

 run more straightly in the interior of a pyramid of Ferrein (fig. 

 167 0), and more crookedly at its circumference, and end in the 

 Malpighian corpuscles, as was shown by Bowman, in 1842, where 

 they come into relation with a plexus of vessels. Examined more 

 closely, after leaving the pyramid, the tubuli uriniferi are seen to 

 become curved laterally (fig. 167 m), some soon after entering the 

 cortical portion, and more and more become so in their passage 

 outwards. They then proceed in an undulating manner towards 

 the arterial trunks which surround the cortical lobules, so that at 

 last either towards the surface of the kidney (and a little distance 

 from it), or towards the middle of the interlobular columns of 

 Bertini, the whole fasciculus is broken up into tortuous tubules. 

 The Malpighian corpuscles (fig. 167 b) are little bodies measuring 

 O'ob'" to O" 1"', from which the tubuli uriniferi arise. They lie in the 

 entire thickness of the cortex from the pyramids onwards to within 

 j\'" from the surface, and they exist in the septa Bertini as far as 

 the pelvis of the kidney. They are arranged so regularly and 

 numerously around the cortical lobules, that, on every perpen- 

 dicular section through the cortex, a red stripe of these corpuscles 

 is always seen between two lobules. As a rule, such a red stripe 

 consists of a small artery and from two to four irregular rows of 

 corpuscles supported on it ; and of these rows, some are related 

 more to the one, others more to the other cortical bundles. Hence, 

 every fasciculus of uriuiferous tubules in the cortex is completely 



