[101] Pouchet, _Théorie de l'Ovulation Spontanée_, 1847. As Blair Bell and Pontland Hick remark ("Menstruation," _British Medical Journal_, March 6, 1909), the repeated oestrus of unimpregnated animals (once a fortnight in rabbits) is surely comparable to menstruation.
[102] Tait, _Provincial Medical Journal_, May, 1891; J. Beard, _The Span of Gestation_, 1897, p. 69. Lawson Tait is reduced to the assertion that ovulation and menstruation are identical.
[103] As Moll points out, even the secondary sexual characters have undergone a somewhat similar change. The beard was once an important sexual attraction, but men can now afford to dispense with it without fear of loss in attractiveness. (_Libido Sexualis_, Band I, p. 387.) These points are discussed at greater length in the fourth volume of these _Studies_, "Sexual Selection in Man."
[104] It is not absolutely established that in menstruating animals the period of menstruation is always a period of sexual congress; probably not, the influence of menstruation being diminished by the more fundamental influence of breeding seasons, which affect the male also; monkeys have a breeding season, though they menstruate regularly all the year round.
[107] See H. Ellis, _Man and Woman_, Chapter XI.
[108] This is by no means true of European women only. Thus, we read in an Arabic book, _The Perfumed Garden_, that women have an aversion to coitus during menstruation. On the other hand, the old Hindoo physician, Susruta, appears to have stated that a tendency to run after men is one of the signs of menstruation.
[109] The actual period of the menstrual flow corresponds, in Heape's terminology, to the congestive stage, or _pro-oestrum_, in female animals; the _oestrus_, or period of sexual desire, immediately follows the _pro-oestrum_, and is the direct result of it. See Heape, "The 'Sexual Season' of Mammals," _Quarterly Journal of Microscopical Science_, 1900, vol. xliv, Part I.
[110] It may be noted that (as Barnes, Oliver, and others have pointed out) there is heightened blood-pressure during menstruation. Haig remarks that he has found a tendency for high pressure to be accompanied by increased sexual appetite (_Uric Acid_, 6th edition, p. 155).
