development of the sexual
system, of congenital character. In a case recorded by Plant
(_Centralblatt fuer Gynaekologie_, No. 9, 1896, summarized in the
_British Medical Journal_, April 4, 1896), in which the internal
sexual organs were almost wholly undeveloped, and menstruation
absent, the labia were similarly undeveloped, and the pubic hair
scanty, while the axillary hair was wholly absent, though that of
the head was long and strong.

We may now regard as purely academic the discussion formerly carried on as
to whether menstruation is to be regarded as analogous to heat in female
animals. For many centuries at least the resemblance has been sufficiently
obvious. Raciborski and Pouchet, who first established the regular
periodicity of ovulation in mammals, identified heat and
menstruation.[101] During the past century there was, notwithstanding, an
occasional tendency to deny any real connection. No satisfactory grounds
for this denial have, however, been brought forward. Lawson Tait, indeed,
and more recently Beard, have stated that menstruation cannot be the
period of heat, because women have a disinclination to the approach of the
male at that time.[102] But, as we shall see later, this statement is
unfounded. An argument which might, indeed, be brought forward is the very
remarkable fact that, while in animals the period of heat is the only
period for sexual intercourse, among all human races, from the very
lowest, the period of menstruation is the one period during which sexual
intercourse is strictly prohibited, sometimes under severe penalties, even
life itself. This, however, is a social, not a physiological, fact.

Ploss and Bartels call attention to the curious contrast, in this
respect, between heat and menstruation. The same authors also
mention that in the Middle Ages, however, preachers found it
necessary to warn their hearers against the sin of intercourse
during the menstrual period. It may be added that Aquinas and
many other early theologians held, not only that such intercourse
was a deadly sin, but that it engendered leprous and monstrous
children. Some later theologians, however, like Sanchez, argued
that the Mosaic enactments (such as Leviticus, Ch. XX, v. 18) no
longer hold good. Modern theologians--in part influenced by the
tolerant traditions of Liguori, and, in part, like Debreyne
(_Moechialogie_, pp. 275 et seq.)