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; a, interlobular artery; 1, vas afferens; 2. vas 

 efferens; r e, vaaa recta ; c, vena rectse ; w u, interlobular vein : S, origin of a vena stellata; i t. Bow- 

 man's capsule and glomerulus; X X, convoluted tubules j i I, I-Ionle's loop; n n, junctional piece; o.o, 

 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 



