122 CORTICAL AND TUBULAR PORTIONS OF THE KIDNEY. 



consist almost entirely of the minute ramifications of these 

 vessels. Among them are some small bodies, which are dis- 

 persed through the substance, like berries on a bush : these are 

 asserted also to be composed of vessels. 



The tubular part certainly proceeds from this vascular 

 cortical substance: for Ruysch, and after him several other 

 injectors, have filled these tubes with injections thrown into the 

 arteries. 



The tubuli, of which this part is composed, seem to arise 

 obscurely from the cortical part. They soon assume somewhat 

 of a radiated direction, and are finally arranged so as to form the 

 papillae or cones above described. 



On these papillae or cones some of them can be traced, uniting 

 with each other, to form larger tubes, which terminate on the 

 surfaces of the papillae, in orifices large enough to be seen dis- 

 tinctly. From these orifices urine may be forced out by com- 

 pressing the papillae. On this account the tubes have been 

 called tubuli uriniferi. 



The minute round bodies (glomeruli) which are distributed 

 like berries on a bush, among the arteries and veins of the 

 cortical portion, and are visible to the naked eye, are called the 

 corpuscles or acini of Malpighi. These bodies, Malpighi and 

 Schumlansky, believed to be hollow sacs, with vessels ramifying 

 on the parietes, and which secreted the urine. Ruysch, Hewson, 

 and more recently Huschke, and Miiller, have shown that they 

 are formed entirely of an agglomeration of minute vascular 

 branches appended to the minute twigs of the arteries, and are 

 mere reservoirs of blood. They vary from the ^ to the ^ Q part 

 of an inch in diameter. 



According to Mr. Bowman* the tuft of capillary vessels of 

 which each glomerule or Malpighian body is composed, is 

 enclosed within the commencing extremity of each uriniferous 

 tube so that the number of these bodies corresponds with 

 the number of uriniferous tubes. By this arrangement the 

 tuft of vessels is received in a sort of funnel shaped dilata- 

 tion of the tube as shown in fig. 153. From the interior of 

 the vascular glomerule, a vein proceeds smaller than the artery 



* London Philosophical Transactions for 1842. 



