43 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



Phosphoric acid is found in the flesh. The animal takes up 

 phosphoric acid when it adds flesh, and it gives off phosphoric 

 acid when it loses flesh. Phosphoric acid is also found in the 

 bones, as phosphates of lime and magnesia. Phosphates are also 

 present in milk. 



An animal which does not receive enough phosphoric acid, 

 lime, and magnesia in its food, loses continually small quantities 

 of phosphates of lime and magnesia. This is removed from its 



Fig. 89. Pens used in feeding experiments. Illinois Station. 



bones, making the bones porous, weak, and liable to break. This 

 diseased condition occurs in some districts where the ' feeding- 

 stuffs do not contain enough lime or phosphoric acid, and may 

 be produced artificially by withholding phosphates from the 

 animal. It may also be caused by an excess of acid in the food. 

 Growing animals which do not receive sufficient lime and phos- 

 phoric acid quickly suffer. Movement becomes painful to them, 



