THE NUTRITION OF PLANTS 
155 
upon respiration, which means the absorption of oxygen by 
the protoplasm, the breaking down of protoplasm, and the 
giving off of carbon dioxide and water as wastes. The im- 
FIG. 146. The common Northern pitcher plant. The hollow leaves, each with a hood 
and a wing, form a rosette, from the center of which arise the flower stalks. 
After KERNER. 
portance of this process may be realized when it is remem- 
bered that there is the same need in our own living, as it 
is essential for us also to "breathe in" oxygen, and as a 
result we "breathe out" carbon dioxide and water. This 
breaking down or "oxidizing" of protoplasm releases the 
