In this connection it is of interest to note the decrees of the Mosaic Law regarding marriage intercourse. Not only was all intercourse with a woman during her menstruation period very heavily punished (see Leviticus xx. 18: "If a man lie with a woman having her sickness ... both of them shall be cut off from among their people"), but the Mosaic Law provided that women should be protected from intercourse for some days _after_ each such period. The results obtained by my independent investigation thus find some support in this ancient wisdom of the East. Modern writers are inclined to deride the Mosaic Law on the ground that it prohibits intercourse just at the time when _they think_ sex feeling should be strongest. But it does not appear on what grounds they make the latter statement, nor do they give any scientific data in support of it. Thus Galabin in his Manual of Midwifery says: "In the Jewish law women are directed to abstain[4] from coitus during menstruation and for seven days after its cessation. Strict observers of the law are said to go beyond what is commanded in Leviticus, and even if discharge lasts only for an hour or two, to observe five days during which the discharge might last, for the period itself, and add to these seven clear days, making twelve in all. It is much to be doubted whether a whole nation was ever induced to practise abstinence at the period of most acute sexual feeling." But, as will readily be recognised, the old Jewish plan of having twelve clear days after the beginning of menstruation before the next union is in almost exact harmony with the Law of Periodicity of Recurrence of women's desire shown in my charts, pp. 32, 33. [4] NOTE.--In Leviticus xv. it is the _man_ who is directed to abstain from touching the woman at this period, and who is rendered unclean if he does.--M. C. S. These comparatively simple curves represent what I would postulate as the normal spontaneous up-welling of natural desire in woman. These are the foundations on which the edifice of the physical expression of love may be built. It must not be forgotten, however, that, particularly in modern luxurious life, there are innumerable excitements which may _stimulate_ sexual feeling, just as there are many factors in our life which tend to inhibit or retard it. A woman may be, like a man, so swayed by a great love that there is not a day in the whole month when her lover's touch, his voice, the memory of his smile, does not stir her into the thrilling longing for the uttermost union. Hence it is often difficult, particularly for a woman dwelling with the man she loves, to recognise this rhythm in herself, for she may be perpetually stimulated by her love and by his being.