tion, vol. ii.)
A full statement of Elliot Smith's investigations, with diagrams,
is given by Bullen, _Journal of Mental Science_, July, 1899. It
may be added that the whole subject of the olfactory centres has
been thoroughly studied by Elliot Smith, as well as by Edinger,
Mayer, and C.L. Herrick. In the _Journal of Comparative
Neurology_, edited by the last named, numerous discussions and
summaries bearing on the subject will be found from 1896 onward.
Regarding the primitive sense-organs of smell in the various
invertebrate groups some information will be found in A.B.
Griffiths's _Physiology of the Invertebrata_, Chapter XI.

The predominance of the olfactory area in the nervous system of the
vertebrates generally has inevitably involved intimate psychic
associations between olfactory stimuli and the sexual impulse. For most
mammals not only are all sexual associations mainly olfactory, but the
impressions received by this sense suffice to dominate all others. An
animal not only receives adequate sexual excitement from olfactory
stimuli, but those stimuli often suffice to counterbalance all the
evidence of the other senses.

We may observe this very well in the case of the dog. Thus, a
young dog, well known to me, who had never had connection with a
bitch, but was always in the society of its father, once met the
latter directly after the elder dog had been with a bitch. He
immediately endeavored to behave toward the elder dog, in spite
of angry repulses, exactly as a dog behaves toward a bitch in
heat. The messages received by the sense of smell were
sufficiently urgent not only to set the sexual mechanism in
action, but to overcome the experiences of a lifetime. There is
an interesting chapter on the sense of smell in the mental life
of the dog in Giessler's _Psychologie des Geruches_, 1894,
Chapter XI, Passy (in the appendix to his memoir on olfaction,
_L'Annee Psychologique_, 1895) gives the result of some
interesting experiments as to the effects of perfume on dogs;
civet and castoreum were found to have the most powerfully
exciting effect.

The influences of smell are equally omnipotent in the sexual life
of many insects. Thus, Fere has found that in cockchafers sexual
coupling failed to take place when the antennae, which are the
organs of smell, were removed; he also found that males, a