but it may last longer--say ten months on rare occasions; and it
may be extended apparently by a delay in fertilisation.

PREVENTION OF CONCEPTION.

For many reasons which I need not enumerate here, the precautions against
impregnation can most easily and effectively be taken by the _woman_,
rather than by the man. She is the one fertilised, and therefore she is
the one to guard herself against fertilisation.

There are _two methods_ of preventing fertilisation:--

(1) _The chemical method_, that is, the destruction of the male
cells (spermatazoa) by means of a suitable germicidal substance,
such as many of the disinfectants; and

(2) _The mechanical method_, that is, the adoption of measures
which keep the male and the female cells apart from one another.

[Illustration: INNER SIDE OF THIGH.

DIAGRAM 1.--Female organs of generation in normal condition. This shows
diagrammatically the position of the organs if a woman were cut in two
between the thighs. The rubber pessary is shown in position, slightly
distending upper end of vagina (or front passage), and covering the
opening into interior of womb. A suppository introduced beforehand will
dissolve and occupy the dotted space above rubber pessary, forming a pool
around the mouth of the womb. The walls of the vagina are elastic and
collapsible. Infection with gonorrhoea may occur in the female urethra (or
water passage) or in the vagina, etc. Syphilis may infect internal and
external parts of female organs; also breasts, mouth, tongue, etc., and
other openings of the body.]

Neither of these two methods in practical application by ordinary women
can be said to be _completely certain_. Both are apt to fail at times. The
chemical method, that is, the application by the woman of a suitable
soluble contraceptive suppository before connection, or of a germicidal
douche (such as a dilute solution of lysol) after connection, or both
these measures taken consecutively, may fail because of some fault in
application, or because the seminal fluid actually enters the womb during
intercourse; that is to say, when emission takes place, the end of the
male organ may be exactly opposite and close to the mouth of the womb, and
the spermatazoa in the seminal fluid enter directly into the womb, and
cannot then be removed or destroyed by douching or contraceptives of any
kind. Now if the physical conformation of the reproductive organs of the
husband and