riage_,
dealing with the question of "A Human Pairing Season in Primitive
Times," brings forward evidence showing that spring, or, rather,
early summer, is the time for increase of the sexual instinct,
and argues that this is a survival of an ancient pairing season;
spring, he points out, is a season of want, rather than
abundance, for a frugivorous species, but when men took to herbs,
roots, and animal food, spring became a time of abundance, and
suitable for the birth of children. He thus considers that in
man, as in lower animals, the times of conception are governed by
the times most suitable for birth.

Rosenstadt, as we shall see later, also believes that men to-day
have inherited a physiological custom of procreating at a certain
epoch, and he thus accounts for the seasonal changes in the
birthrate.

Heape, who also believes that "at one period of its existence the
human species had a special breeding season," follows Wiltshire
in suggesting that "there is some reason to believe that the
human female is not always in a condition to breed." (W. Heape,
"Menstruation and Ovulation of _Macacus rhesus_," _Philosophical
Transactions_, 1897; id. "The Sexual Season of Mammals,"
_Quarterly Journal Microscopical Science_, 1900.)

Except, however, in one important respect, with which we shall presently
have to deal, few attempts have been made to demonstrate any annual
organic sexual rhythm. The supposition of such annual cycle is usually
little more than a deduction from the existence of the well-marked
seasonal sexual rhythm in animals. Most of the higher animals breed only
once or twice a year, and at such a period that the young are born when
food is most plentiful. At other periods the female is incapable of
breeding, and without sexual desires, while the male is either in the same
condition or in a condition of latent sexuality. Under the influence of
domestication, animals tend to lose the strict periodicity of the wild
condition, and become apt for breeding at more frequent intervals. Thus
among dogs in the wild state the bitch only experiences heat once a year,
in the spring. Among domesticated dogs, there is not only the spring
period of heat, early in the year, but also an autumn period, about six
months later; the primitive period, however, remains the most important
one, and the best litters of pups are said to be produced in