in the brain of reptiles the
"area olfactoria" is of enormous extent, covering, indeed, the greater
part of the cortex, though it may be quite true, as Herrick remarks, that,
while smell is preponderant, it is perhaps not correct to attribute an
exclusively olfactory tone to the cerebral activities of the _Sauropsida_
or even the _Ichthyopsida_. Among most mammals, however, in any case,
smell is certainly the most highly developed of the senses; it gives the
first information of remote objects that concern them; it gives the most
precise information concerning the near objects that concern them; it is
the sense in terms of which most of their mental operations must be
conducted and their emotional impulses reach consciousness. Among the apes
it has greatly lost importance and in man it has become almost
rudimentary, giving place to the supremacy of vision.

Prof. G. Elliot Smith, a leading authority on the brain, has well
summarized the facts concerning the predominance of the olfactory
region in the mammal brain, and his conclusions may be quoted. It
should be premised that Elliot Smith divides the brain into
rhinencephalon and neopallium. Rhinencephalon designates the
regions which are pre-eminently olfactory in function: the
olfactory bulb, its peduncle, the tuberculum olfactorium and
locus perforatus, the pyriform lobe, the paraterminal body, and
the whole hippocampal formation. The neopallium is the dorsal cap
of the brain, with frontal, parietal, and occipital areas,
comprehending all that part of the brain which is the seat of the
higher associative activities, reaching its fullest development
in man.

"In the early mammals the olfactory areas form by far the greater
part of the cerebral hemisphere, which is not surprising when it
is recalled that the forebrain is, in the primitive brain,
essentially an appendage, so to speak, of the smell apparatus.
When the cerebral hemisphere comes to occupy such a dominant
position in the brain it is perhaps not unnatural to find that
the sense of smell is the most influential and the chief source
of information to the animal; or, perhaps, it would be more
accurate to say that the olfactory sense, which conveys general
information to the animal such as no other sense can bring
concerning its prey (whether near or far, hidden or exposed), is
much the most serviceable of all th