Studies in the Psychology of Sex (Vol. 1-6). Havelock Ellis
the Reproductive Organs of Woman," in his Nervous Diseases of Women, 1840, pp. 61–70) much interesting evidence to show that the system undergoes changes about the vernal and autumnal equinoxes, and that these changes are largely sexual.
Edward Smith, also a notable pioneer in this field of human periodicity, and, indeed, the first to make definite observations on a number of points bearing on it, sums up, in his remarkable book, Health and Disease as Influenced by Daily, Seasonal, and Other Cyclical Changes in the Human System (1861), to the effect that season is a more powerful influence on the system than temperature or atmospheric pressure; "in the early and middle parts of spring every function of the body is in its highest degree of efficiency," while autumn is "essentially a period of change from the minimum toward the maximum of vital conditions." He found that in April and May most carbonic acid is evolved, there being then a progressive diminution to September, and then a progressive increase; the respiratory rate also fell from a maximum in April to a minimum maintained at exactly the same level throughout August, September, October, and November; spring was found to be the season of maximum, autumn of minimum, muscular power; sensibility to tactile and temperature impressions was also greater in spring.
Kulischer, studying the sexual customs of various human races, concluded that in primitive times, only at two special seasons—at spring and in harvest-time—did pairing take place; and that, when pairing ceased to be strictly confined to these periods, its symbolical representation was still so confined, even among the civilized nations of Europe. He further argued that the physiological impulse was only felt at these periods. (Kulischer, "Die geschlechtliche Zuchtwahl bei den Menschen in der Urzeit," Zeitschrift für Ethnologie, 1876, pp. 152 and 157.) Cohnstein ("Ueber Prädilectionszeiten bei Schwangerschaft," Archiv für Gynäkologie, 1879) also suggested that women sometimes only conceive at certain periods of the year.
Wiltshire, who made various interesting observations regarding the physiology of menstruation, wrote: "Many years ago, I concluded that every women had a law peculiar to herself, which governed the times of her bringing forth (and conceiving); that she was more prone to bring forth at certain epochs than at others; and subsequent researches have established the accuracy of the forecast." He further stated his belief in a "primordial seasonal aptitude for procreation, the impress of which still remains, and, to some extent, governs the breeding-times of humanity." (A. Wiltshire, "Lectures on the Comparative Physiology of Menstruation," British Medical Journal, March, 1883, pp. 502, etc.)
Westermarck, in a chapter of his History of Human Marriage, 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 the spring. The mare is in season in spring and summer; sheep take the ram in autumn.[128] Many of the menstruating monkeys also, whether or not sexual desire is present throughout the year, only conceive in spring and in autumn. Almost any time of the year may be an animal's pairing season, this season being apparently in part determined by the economic conditions which will prevail at birth. While it is essential that animals should be born during the season of greatest abundance, it is equally essential that pairing, which involves great expenditure of energy, should also take place at a season of maximum physical vigor.
As an example of the sexual history of an animal through the year, I may quote the following description, by Dr. A. W. Johnstone, of the habits of the American deer: "Our common American deer, in winter-time, is half-starved for lack of vegetation in the woods; the low temperature, snow, and ice, make his conditions of life harder for lack of the proper amount of food, whereby he becomes an easier prey to carnivorous animals. He has difficulty even in preserving life. In spring he sheds his winter coat, and is provided with a suit of lighter hair, and while this is going on the male grows antlers for defence. The female about this time is far along in pregnancy, and when the antlers are fully grown she drops the fawn. When the fawns are dropped vegetation is plentiful and lactation sets in. During this time the male is kept fully employed in getting food and guarding his more or less helpless family. As the season advances the vegetation increases and the fawn begins to eat grass. When the summer heat commences the little streams begin to dry up, and the animal once more has difficulty in supporting life because of the enervating heat, the effect of drought on the vegetation, and the distance which has to be traveled to get water; therefore, fully ten months in each year the deer has all he can do to live without extra exertion incident to rutting. Soon after the autumn rains commence vegetation becomes more luxurious, the antlers of the male and new suits of hair for both are fully grown, heat of the summer is gone, food and drink are plentiful everywhere, the fawns are weaned, and both sexes are in the very finest condition. Then, and then only, in the whole year, comes the rut, which, to them as to most other animals, means an unwonted amount of physical exercise besides the everyday runs for life from their natural enemies, and an unusual amount of energy is used up. If a doe dislikes the attention of a special buck, miles of racing result. If jealous males meet, furious battles take place. The strain on both sexes could not possibly be endured at any other season of the year. With approach of cold weather, climatic deprivations and winter dangers commence and rut closes. In all wild animals, rut occurs only when the climatic and other conditions favor the highest physical development. This law holds good in all wild birds, for it is then only that they can stand the strain incident to love-making. The common American crow is a very good study. In the winter he travels around the ricefields of the South, leading a tramp's existence in a country foreign to him, and to which he goes only to escape the rigors of the northern climate. For several weeks in the spring he goes about the fields, gathering up the worms and grubs. After his long flight from the South he experiences several weeks of an almost ideal existence, his food is plentiful, he becomes strong and hearty, and then he turns to thoughts of love. In the pairing season he does more work than at any other time in the year: fantastic dances, racing and chasing after the females, and savage fights with rivals. He endures more than would be possible in his ordinary physical state. Then come the care of the young and the long flights for water and food during the drought of the summer. After the molt, autumn finds him once more in flock, and with the first frosts he is off again to the South. In the wild state, rut is the capstone of perfect physical condition." (A. W. Johnstone, "The Relation of Menstruation to the other Reproductive Functions," American Journal of Obstetrics,