THE KIDNEY. 



213 



The blood-vessels of the kidney. The renal artery and vein, 

 before entering the hilum, divide and subdivide within the 

 sinus of the kidney. Small branches, which are given off at 

 the hilum, also supply the fibrous capsule of the gland. Veins 

 accompany the arteries as far as the arches already referred to. 

 But here a difference is to be noted. The arteries never anas- 

 tomose, but form the straight vessels of the cortical substance 

 proper, which again send off twigs to form the glomeruli. 



Pio. 99. Kidney of pig. Injection of artery and vein. Vertical section at bonndary layer : A, 

 artery ; B, vein : C, gloaierulus ; D, capillaries of the cortical portion ; E, vasa recta formed from 

 capillaries D. x 96. 



At the arches, however, the veins anastomose, and a branch 

 accompanies the straight artery of the cortical substance proper 

 (Fig. 99, B). The glomerulus is formed from the arterial twig 

 above referred to (Fig. 89, D). This enters the capsule directly 

 opposite to the point where the latter becomes continuous 

 with a convoluted tubule, and divides into two or more 



its first portion. The expanded part of the ascending loop is lined with cells having 

 very thick prominent rods, and whose lumen is exceedingly small. 



The irreg-'itar tubule has an angular, irregular outline, is of very varying diameter, 

 in some portions two, three, or four times as broad as in other portions, a condition 

 due to its peculiar lining epithelia, which are angular and present numerous pro- 

 cesses ; the rods are exceedingly thick and prominent. 



As yet I have been unable to confirm Schachowa's researches. 



