12 HUMAN PHYSIOLOGY 



sulphur, iron, phosphorus, magnesium, and other less 

 familiar substances. Our elements therefore pre- 

 sent nothing distinctive. These elements combine, 

 moreover, to form compounds. Some of the latter 

 (water, common salt, phosphate of lime, chalk, etc.) 

 are also common in the world around us ; but other 

 compounds, formed by the elements noted (proto- 

 plasm or living matter, fat, starch, sugar, etc.) are 

 peculiar to animals and plants. It is this power of 

 building up the latter class of compounds which dis- 

 tinguishes living beings. The body of a man, taking 

 it at 100, is composed of water, 61*0 per cent; 

 minerals, 5*5; bony matter, 18'0; starch and sugar, 

 O'l ; and fat, 15*4. 



