of Ishtar (the Kadishtu, or “holy ones”) were prostitutes, but by the statements in Babylonian legends concerning the state of the earth during Ishtar’s winter absence, when the bull, the ass, and man ceased to reproduce.  It is evident that the return of spring, coincident with the Tammuz festival, was regarded as the period for the return of the reproductive instinct even in man.[147] So that along this line also we are led back to a great procreative festival.

Thus the great spring festivals were held between March and June, frequently culminating in a great orgy on Midsummer’s Eve.  The next great season of festivals in Europe was in autumn.  The beginning of August was a great festival in Celtic lands, and the echoes of it, Rhys remarks, have not yet died out in Wales.[148] The beginning of November, both in Celtic and Teutonic countries, was a period of bonfires.[149] In Germanic countries especially there was a great festival at the time.  The Germanic year began at Martinmas (November 11th), and the great festival of the year was then held.  It is the oldest Germanic festival on record, and retained its importance even in the Middle Ages.  There was feasting all night, and the cattle that were to be killed were devoted to the gods; the goose was associated with this festival.[150] These autumn festivals culminated in the great festival of the winter solstice which we have perpetuated in the celebrations of Christmas and New Year.  Thus, while the two great primitive culminating festivals of spring and autumn correspond exactly (as we shall see) with the seasons of maximum fecundation, even in the Europe of to-day, the earlier spring (March) and—­though less closely—­autumn (November) festivals correspond with the periods of maximum spontaneous sexual disturbance, as far as I have been able to obtain precise evidence of such disturbance.  That the maximum of physiological sexual excitement should tend to appear earlier than the maximum of fecundation is a result that might be expected.

The considerations so far brought forward clearly indicate that among primitive races there are frequently one or two seasons in the year—­especially spring and autumn—­during which sexual intercourse is chiefly or even exclusively carried on, and they further indicate that these primitive customs persist to some extent even in Europe to-day.  It would still remain, to determine whether any such influence affects the whole mass of the civilized population and determines the times at which intercourse, or fecundation, most frequently takes place.

This question can be most conveniently answered by studying the seasonal variation in the birthrate, calculating back to the time of conception.  Wargentin, in Sweden, first called attention to the periodicity of the birthrate in 1767.[151] The matter seems to have attracted little further attention until Quetelet, who instinctively scented unreclaimed fields of statistical investigation, showed that in Belgium and Holland there