24 THE NATURE-STUDY OF PLANTS 
also from being scorched and dried up in the hot 
sunshine, and drought is one of the greatest difficulties 
with which plants have to contend, for loss of water 
soon spells loss of life. Among many other such 
protective structures there are the bark of our trees 
and the waxy bloom that we find upon such fruits 
as sloes and such leaves as those of our garden car- 
nations and pinks. Bark is composed of dead cells 
which form a thick protective covering over the 
delicate living cells within, and if we bear in mind how 
absolutely essential it is for plants to avoid being 
dried up we shall soon discover many other delightful 
protective contrivances. 
In drawing attention, however, to the paramount 
importance of an adequate supply of water, I must 
caution the reader that there is such a thing as water 
in the wrong place. The right places, so far as our 
land plants are concerned, are inside the cells or in 
the soil where it can be absorbed by the root-hairs ; 
the wrong places are, amongst others, on the skin 
of the leaves or inside the flowers. 
If the pores were to become choked with water 
it would soon compromise both respiration and nutri- 
tion, hence hairy or waxy leaves serve a double 
purpose so far as water is concerned; for while 
helping to conserve the internal supply they are a 
protection against it in the wrong place externally ; 
neither the rain nor the dew can reach the skin and 
choke the pores of a hairy leaf, and water runs off the 
waxy ones as readily as off a duck’s back. 
There is also another happening of similar signifi- 
cance that I must not omit to mention because it 
is often, but quite erroneously, spoken of as Sleep, and 
I may as well say at once that there is no such thing 
