18 THE FEEDING OF ANIMALS 



found in all soils and natural waters and in all the higher 

 forms of animal and vegetable life. We know it as "brim- 

 stone" when fused in sticks and as "flowers of sulfur" 

 when in a finely divided form. Its most common com- 

 mercial compounds are sulfuric acid and the sulfates of 

 potassium, sodium, calcium, and magnesium. Sulfur is an 

 element essential to the building up of some of the most 

 important tissues of the animal body and is supplied in 

 food in the form of the sulfates and in protein com- 

 binations. (See Par. 64.) 



17. Phosphorus. This element occupies a very impor- 

 tant place in animal nutrition. It does not exist in nature 

 in an uncombined form and that found in laboratories is 

 produced only by chemical means, but its compounds are 

 widely distributed, those in the soil being chiefly the 

 phosphates of calcium, magnesium, and iron. Large 

 deposits of calcium phosphate are known, from which is 

 obtained the crude phosphatic rock that serves as a basis 

 for the manufacture of commercial fertilizers. All feeding- 

 stuffs in their natural forms contain phosphorus com- 

 pounds, such as phosphates, certain fats, and organic 

 nitrogen compounds. Phosphorus is a constituent of the 

 flesh of animals, and, combined with lime, constitutes a 

 large part of bone. (See Par. 55.) 



18. Chlorine. The chief source of chlorine to animal 

 life is common salt. In some form or combination it is 

 essential to the nutrition of the animal. In a free state, 

 at ordinary temperatures, it is a greenish colored, dis- 

 agreeable gas. When combined with hydrogen, it forms 

 hydrochloric acid a compound that occupies a promi- 

 nent place in the digestion of food. Any ordinary mixed 

 ration contains this element in a quantity sufficient for 

 the animal's needs. (See Par. 144.) 



