644 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



The principal constituent of the urine which is removed by a process 

 of filtration is, of course, water. Therefore, in the quantity of urine, 



Fig. 268.— Blood-Vessels and Uriniferous Tubules of the Kidney 

 (Semi-diagrammatic). (Landois.) 

 A, capillaries of the cortex ; B. of the medulla ; <?, interlobular artery ; 1, vas afferens ; 2, vas 

 eflereus ; r e, vasa recta : c, venie rectte ; u u, interlobular vein ; S, origin of a vena stellata ; i i. Bow- 

 man's capsule and glomerulus; X X. convoluted tubules ; tt. Henle's loop; /in, junctional piece; oo, 

 collecting tubes ; O, excretory tube. 



which, of course, means quantity of water, the variations in the activity 

 of the process of filtration may be mainly made out. Wherever the 



