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If she will place in colored water the stem of a large 
white tulip, cutting off its lower end under the liquid, 
those parts whose little cells are in closest connection 
with the stem will soon begin to change color, taking 
the red or blue of the water; for a freshly cut stem has 
the same power as the root to suck in water eagerly and 
quickly. 
HOW AVPLANT PERSEIRES 
FE cannot see the water as it passes from the tiny 
leaf mouths into the air. Neither can we see 
the water that is being constantly carried from the sur- 
face of our bodies into the air. Butif we breathe against 
a window pane, the scattered water in our breath is 
collected by the cold of the glass in a little cloud; and 
if we place the warm palms of our hands against this 
window pane, in the same way the cold collects the 
water that is passing from the little mouths in our skin, 
and shows it to us as a cloud on the glass. 
Heat scatters water so that we cannot see it, any 
more than we can see the lump of sugar when its little 
grains are scattered in hot water; but cold gathers 
together the water drops so that we are able to see them. 
This is why you can “see your breath,” as you say, 
on a cold day. The cold outside air gathers together 
the water which was scattered by the heat of your body. 
If you place against the window pane the under side 
of the leaves of a growing plant, the water passing 
from the tiny leaf mouths collects on the glass in just 
