furnish some of the weaker, more unprotected species with a means of
escape from their enemies. The most stinking example I know is that of a
large hairy caterpillar I have found on dry wood in Patagonia, and
which, when touched, emits an intensely nauseous effluvium. Happily it
is very volatile, but while it lasts it is even more detestable than
that of the skunk.

The skunk itself offers perhaps the one instance amongst the higher
vertebrates of an animal in which all the original instincts of
self-preservation have died out, giving place to this lower kind of
protection. All the other members of the family it belongs to are
cunning, swift of foot, and, when overtaken, fierce-tempered and well
able to defend themselves with their powerful well-armed jaws.

For some occult reason they are provided with a gland charged with a
malodorous secretion; and out of this mysterious liquor Nature has
elaborated the skunk's inglorious weapon. The skunk alone when attacked
makes no attempt to escape or to defend itself by biting; but, thrown by
its agitation into a violent convulsion, involuntarily discharges its
foetid liquor into the face of an opponent. When this animal had once
ceased to use so good a weapon as its teeth in defending itself,
degenerating at the same time into a slow-moving creature, without fear
and without cunning, the strength and vileness of its odour would be
continually increased by the cumulative process of natural selection:
and how effective the protection has become is shown by the abundance of
the species throughout the whole American continent. It is lucky for
mankind--especially for naturalists and sportsmen--that other species
have not been improved in the same direction.

But what can we say of the common deer of the pampas (Cervus