6 MALPIGHIAN BODIES. 



they converge from the papillae of the pyramids of Malpighi, 

 on which they open; on reaching the cortical portion, the 

 straight tubes split up into a radiating arrangement of con- 

 voluted tubes; these combinations of convoluted tubes are 

 called pyramids of Ferrein. The convoluted tubes terminate 

 by flask-shaped pouches, which embrace a tuft of renal 

 capillaries; these tufts with their pouches are called Mal- 

 pighian bodies, (after the distinguished Italian anatomist 

 who first described them). The Malpighian bodies occupy 

 the cortical portion of the kidney, and may be seen as 

 minute red points dotting its surface (Fig. 153). Each 

 Malpighian body is supplied by a renal artery (called the 

 afferent vessel); on entering the flask- 

 shaped pouch, it breaks up into capil- 

 laries, from which there arises a vein (the 

 efferent vessel) ; this vein breaks up into 

 a second network, embracing and sup- 

 plying the convoluted portion of the 

 uriniferous tube (Fig. 154.) This second 

 set of capillaries uniting, form the renal 

 vein. The epithelium lining the tubuli 

 uriniferi is spheroidal. 



The rather minute description of the 



Fig. 154.-Plan of Renal . . * 



circulation, a, Artery; 6, kidney which has preceded, is essential, 

 vein - c Malpighian body; ^ order th t it physiology may be under- 



d, Uriniferous tube. " J &J J 



stood. The various portions of the tubuli 

 uriniferi are supposed by modern physiologists to have dif- 

 ferent functions. In the Malpighian body, the watery con- 

 stituents of the urine alone are supposed to transude from 

 the capillaries ; in the convoluted portion, the solids of the 

 urine are said to be separated, and in part formed, while 

 the straight portion of the tubes seems to be destined to carry 

 off the secreted urine to the pelvis of the kidney. 



