22 . The Feeding of Animals 



Carbon constitutes a larger proportion of the dry- 

 substance of plants than any other element, and there 

 is certainly no species that is an exception to this rule. 

 Oxygen stands next in order, followed by hydrogen, 

 and then nitrogen. It is an important fact in the 

 economy of nature that those elements which, on the 

 average, make up 93.5 per cent of the dry matter of 

 plants have as their main source either the atmosphere 

 or water. Only a small percentage of the dry matter of 

 the farmer's crops is drawn from the soil, and it there- 

 fore follows that it is this small proportion of the mass 

 of matter that makes up the inorganic world which 

 sustains the most important economic and financial 

 relations to the farmer's business. 



The elements of the ash vary somewhat in different 

 plants. For illustration, their proportions in the dry 

 matter of the maize plant in bloom are given in this 

 connection : 



Per cent 



Phosphorus 20 



Silicon 51 



Sulfur 07 



Chlorine 29 



Potassium 1.78 



Sodium 19 



Calcium 72 



Magnesium 39 



Iron 10 



Oxygen combined with the above 1.73 



Total per cent 6.04 



In animals. — We are not ignorant of the propor- 

 tions of the chemical elements in the bodies of our 



