1 8 FUNCTION OF LEAVES [chap 



matters and suppose that this has been already done, and 

 that you tried the experiment in this way upon three 

 distinct specimens. No. i you left lying upon the table. 

 No. 2 was placed vvith its root in water. No. 3 was hung 

 upside down, with a flower or leaf in water, the roots in 

 the air 



The general result of your experiment will be as follows : 

 — After the lapse of a few hours, No. i will be, as we have 

 already found, faded ; No. 2 will be nearly unaltered ; No. 3 

 will be partially faded, the parts out of water especially. 

 Hence we may gather that water supplied to the specimens 

 prevents them from fading, especially if it be supplied to 

 the root. On the other hand, if water be withheld, they 

 fade. 



2. If we take now the faded specimen first described and 

 put its root in water, and leave it for a few hours in a cool, 

 shaded room, we shall probably find, unless it be irre- 

 trievably withered, that it freshens more or less ; the leaves 

 and stem become firmer and more nearly hke their 

 original state. 



This experiment shows us, further, that water supplied to 

 a fading plant enables it to recover. 



Reflecting upon these experiments, we shall be led to 

 the following conclusions : — 



i. That water evaporates from the exposed surface of 



plants. 

 ii. That fresh supplies are taken into the plant by the 



root. 

 iii. That the stem serves to convey this water-supply from 

 the root to the leaves. 



3. We may now try another simple experiment, devised 

 by Professor Henslow, which shows that exposure to direct 

 sunlight, as well as dryness of the air, has to do with this 



