months, 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