THE KIDNEYS. 73 



senting this granular appearance, and is of a dark or reddish 

 brown colour, varying considerably, however, according to 

 the cause of death. 



The granular corpuscles which form the mass of the cortical 

 or secretory substance, are, individually, imperfectly visible to 

 the naked eye, and appear like rounded points. 



The celebrated Ruysch, who was distinguished for the suc- 

 cess of his injections, and for the acuteness of his vision, de- 

 clared that they consisted wholly in the very fine extremities 

 of arteries and veins having a penicillous arrangement; while 

 Malpighi and Schumlansky viewed them as purses or small 

 sacs of a glandular character, specifically suited to secrete 

 urine, and upon whose parietes the blood vessels ramified. 

 From these granuli or acini the incipient extremities of the tu- 

 buli uriniferi take their rise. 



The Tubular or Conoidal portion, consists in from twelve to 

 eighteen conoidal fasciculi (Pyramides Malpighiance) present- 

 ing their rounded bases towards the cortical matter, and en- 

 closed in it, while their apices converge to the central cavity of 

 the kidney, the surface of which they form. The bodies of 

 these pyramids, as just mentioned, are separated by processes 

 of the cortical matter; but their apices are free, and project 

 from the internal surface of the kidney so as to resemble as 

 many small nipples, whence they are called Papillae Renales. 

 Frequently two of the pyramids coalesce so as to form but one 

 papilla together; in such case the latter generally preserves a 

 duplicate appearance. The papillae are arranged into three ver- 

 tical rows, one before, one in the middle, and another behind: 

 those of the foremost row are turned backwards; those of the 

 middle look inwards; and those behind look forwards. Mot un- 

 frequently, there is a small depression (foveola) on the very 

 summit of the papilla. The tubular part is of a lighter colour 

 and harder than the cortical, but the difference in these respects 

 is not always manifest. 



The conoidal fasciculi may each be considered, along with its 

 appertaining cortex, as a sort of distinct gland, or at least as a 

 lobe; for upon them depends the lobulated appearance of the 

 kidneys of a foetus, and of animals. Each cone, when analyzed, 

 is found to consist in a collection of tubes (Duclus Uriniferi 

 Bellini) converging from the circumference of the kidney to 



VOL. II. 8 



