The Skin and the Kidneys 



203 



of urea and other waste products from the surrounding 

 capillaries. 



Thus by a peculiar and delicate kind of filtering process 

 the fluid portions of the renal secretion with soluble salts, and 

 the urea with other waste material are separated from the blood. 



FIG. 1 10. Vertical Section of the Back. 



(Showing kidneys in situ and the relative position of adjacent organs and vessels. 

 Posterior view.) A, i2th dorsal vertebra; B, diaphragm; C, receptaculum 

 chyli ; D, small intestines. 



