2OO 



EXCRETION BY THE KIDNEYS AND SKIN 



indicate some control over the activity of the kidneys by the 

 nervous system; but that influence is probably exerted only 

 through vase-constrictor and vaso-dilator fibers to the vessels. 

 Assuming for the present that nearly all the constituents of 



FIG. 59. Blood-vessels of the kidney. 



A, capillaries of cortex; B, of medulla; a, interlobular artery; i, vas afferens; 2, 

 vas efferens; *', e, vasa recta; VV, interlobular vein; S, origin of a stellate vein; i, i, 

 Bowman's capsule and glomerules: P, apex of papilla; C, capsule of kidney; e, vasa 

 recta from lowest vas efferens. (Stirling.) 



