HOW A PLANT FEEDS. 
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procure enough to make up for the loss from the 
leaves the plant droops. 
10. The dissolved mineral food brought in from 
the soil, however, does not pass off with the water, 
but remains in the plant, to help in forming fresh 
growths. 
n. Some kinds of plants give off water from their 
leaves much more freely than others. A tobacco 
plant will give off nearly a quart a day, and a 
guango-tree twenty or more gallons daily. Only 
think what an enormous amount of vapour must 
be poured into the air from a forest or plantation ! 
This work is almost all done in the daylight, as 
at night the little pores in the leaves close. 
HOW A PLANT FEEDS.— II. 
1. We have already seen that plants take in 
some food as well as a large quantity of water by 
their roots; but by far the larger part of their food 
is taken in by the leaves. This food is a gas, called 
carbon dioxide or carbonic acid, which is always 
present in small quantities in the air. 
2. The leaves spread themselves out, and take in 
the gas they need through tiny openings, called 
stomata, in the under surface. To understand what 
happens afterwards, you must know that this gas is 
made up of two things — of oxygen gas and carbon. 
