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ANIMAL BIOLOGY 



Malpighian corpuscle which consists of a thin- walled capsule 

 surrounding a knot of blood vessels, the glomerulus. 

 These tubules after a tortuous course lead to a cavity 

 which is connected with the ureter. The uriniferous 

 tubules which we may call the drain pipes of the body re- 

 move a considerable quantity of water and various salts 

 from the blood, but their most important function is the 

 elimination of urea which is a nitrogenous compound re- 



PIG. 204. Vertical section through kidney. 2, pyramid showing the 

 renal tubules opening at the papillae, 3; 4, pelvis or cavity of kidney; 5, 

 ureter; 6, renal artery; 7, renal vein; 8, branches of these blood vessels. 

 (After Leidy.) 



suiting from the breaking down of proteins. The elimina- 

 tion of water affords the means of getting rid of solid 

 waste products in the blood, because these substances 

 must be in a state of solution in order to be discharged 

 from the body. Most people would be better off if they 

 drank more water so as to wash their protoplasm free from 

 its various injurious impurities. We are all poisonous to 

 ourselves. When disease of the kidneys impairs their 

 activities poisons accumulate in the body and death may 



