a tendency to be vulgar, which is another mystery inciting us to
investigate it. So let us proceed.

The first thing required by the principles of scientific precedure is a
definition. What is a nose? But this proves to be a much more difficult
question than anyone would suspect before he tried to answer it. The
individual human nose we can recognise, describe or sketch more easily
than any other feature, but try to define the thing _nose_ in Nature and
it is a most elusive phenomenon. When we speak of a man being led by the
nose we imply that it is a part of him which is prominent and situated
in front, when we speak of keeping one's nose above water we refer to it
as the breathing orifice, but when we say that this or that offends our
nose we are regarding it as the seat of the sense of smell. I believe
that all these three ideas must be included in any definition. It should
follow that insects, which breathe through holes in their sides, cannot
have noses, and this is the truth.

Fishes, too, though they may have snouts, have not noses, because they
breathe by gills. In truth, it seems that the nose was a very late and
high acquisition, almost the finishing touch of the perfected animal
form. And incidentally this leads us to notice what a great step was
taken in evolution when the breathing holes were brought up to the
region of the mouth. For the sense of taste is necessarily situated in
the mouth, and the sense of smell is in close alliance with it. The
mouth tastes food dissolved in the saliva during the process of
mastication, and the primary use of the sense of smell is to detect and
analyse beforehand the small particles given off by food and floating in
the atmosphere.

A good many years ago, when the late Sally chimpanzee was the darling of