ule,
the sting is the only point in the whole organization of the family over
which we ever waste a single thought. This is our ordinary human
narrowness; in each plant or animal we interest ourselves about that one
part alone which has special reference to our own relations with it, for
good or for evil. In a strawberry, we think only of the fruit; in a
hawthorn, or the flowers; in a deadly nightshade, of the poisonous
berry; and in a nettle, of the sting. Now, I frankly admit at the
present moment that the nettle sting has an obtrusive and unnecessarily
pungent way of forcing itself upon the human attention; but it does not
sum up the whole life-history of the plant in its own one peculiarity
for all that. The nettle exists for its own sake, we may be sure, and
not merely for the sake of occasionally inflicting a passing smart upon
the meddlesome human fingers.

However, the sting itself, viewed philosophically, is not without
decided interest of its own. It is one, and perhaps the most highly
developed, among the devices by which plants guard themselves against
the attacks of animals. Weeds and shrubs with juicy, tender leaves are
very apt to be eaten down by rabbits, cows, donkeys and other
herbivores. But if any individuals among such species happen to show any
tendency to the development of any unpleasant habit, which prevents the
herbivores from eating them, then those particular individuals will of
course be spared when their neighbors are eaten, and will establish a
new and specially protected variety in the course of successive
generations. It does not matter what the peculiarity may be, provided
only it in any way deters animals from eating the plant. In the arum, a
violently acrid juice is secreted in the leaves, so as to burn the mouth
of the aggressor. In the dandelion and wild lettuces, the juice is
merely bitter. In houndstongue and catmint it has a nauseous taste. Then
again, in the hawthorn and the blackthorn, some of the shorter branches
have developed into stout, sharp spines, which tear the skin of would-be
assailants. In the brambles, the hairs on the stem have thickened into
pointed prickles, which answer the same purpose as the spines of their
neighbors. In the thistles, the gorse and the holly, once more, it is
the angles of the leaves themselves, which have grown into needle-like
points so as to deter animals from browsing upon them. But the nettle
probably carries the same tendency to the furt