when the harvest-working months for the population are over, and the period of rest, and also of minimum deathrate (September, October, and November), comes round.  In Russia the general conception-rate has been studied by various investigators.  Here the maximum number of conceptions is in winter, the minimum varying among different elements of the population.  Looked at more closely, there are maxima of conceptions in Russia in January and in April. (In Russian towns, however, the maximum number of conceptions occurs in the autumn.) The special characteristics of the Russian conception-rate are held to be due to the prevalence of marriages in autumn and winter,[154] to the severely observed fasts of spring, and to the exhausting harvest-work of summer.

It is instructive to compare the conception-rate of Europe with that of a non-European country.  Such a comparison has been made by S.A.  Hill for the Northwest Provinces of India.  Here the Holi and other erotic festivals take place in spring; but spring is not the period when conceptions chiefly take place; indeed, the prevalence of erotic festivals in spring appears to Hill an argument in favor of those festivals having originated in a colder climate.  The conceptions show a rise through October and November to a maximum in December and January, followed by a steady and prolonged fall to a minimum in September.  This curve can be accounted for by climatic and economic conditions.  September is near the end of the long and depressing hot season, when malarial influences are rapidly increasing to a maximum, the food-supply is nearly exhausted, and there is the greatest tendency to suicide.  With October it forms the period of greatest mortality.  December, on the other hand, is the month when food is most abundant, and it is also a very healthy month.[155]

For a summary of the chief researches into this question, see Ploss and Bartels, Das Weib; also, Rosenstadt, “Zur Frage nach den Ursachen welche die Zahl der Conceptionen, etc,” Mittheilungen aus den embryologischen Institute Universitaet Wien, second series, fasc. 4, 1890.  Rosenstadt concludes that man has inherited from animal ancestors a “physiological custom” which has probably been further favored by climatic and social conditions.  “Primitive man,” he proceeds, “had inherited from his ancestors the faculty of only reproducing himself at determined epochs.  On the arrival of this period of rut, fecundation took place on a large scale, this being very easy, thanks to the promiscuity in which primitive man lived.  With the development of civilization, men give themselves up to sexual relations all the year around, but the ‘physiological custom’ of procreating at a certain epoch has not completely disappeared; it remains as a survival of the animal condition, and manifests itself in the recrudescence of the number of conceptions during certain months of the year.”  O. Rosenbach ("Bemerkungen ueber das Problem einer Brunstzeit beim Menschen,”