90 FOUNDATIONS OF BIOLOGY 



and proteins must be oxidized, that is, burned, and conse- 

 quently free oxygen transmitted throughout the plant to the 

 various cells, and carbon dioxide carried away. This is 

 effected by an intercellular system of air spaces which rami- 

 fies throughout the plant and communicates with the sur- 

 rounding atmosphere chiefly by way of the stomata. 



We have now considered, in such detail as the scope of the 

 present work requires, the structure and functions of a typical 

 higher plant as a whole, and have indicated how the organ- 

 ism is specialized for the chief function which primarily 

 concerns the individual; that is, nutrition, or the trans- 

 formation of matter and energy into life and work. Since, 

 however, the duration of the existence of the individual is 

 relatively limited, it is obvious that some provision must 

 exist for the continuation of the race. In other words new 

 individuals must be formed. This brings us to the second 

 great function of the organism, reproduction. 



