In order to procreate the human species, there is a periodical discharge
of blood from the vagina of every female, termed the catamenia, or
menses. The secretion of this fluid commences at that period of life
termed puberty, which occurs at different ages, according to the
climate. In some latitudes it commences as early as eight or ten, and in
others not until fifteen. As soon as conception or pregnancy commences,
this discharge ceases, and goes to support the fœtus, or the child.
The manner in which conception takes place has ever been a fruitful
subject of inquiry, but we are unable to account for this change
precisely. It is, however, pretty evident that the semen of the male is
introduced into the uterus, while the semen of the female is discharged
from the ovaria by means of the Fallopian tubes, the fimbricated
extremity of which closely embraces that organ.
These tubes, by a kind of peristaltic motion similar to the intestines,
convey the semen of the female into the uterus, where it unites with the
semen of the male; and it is these united fluids which constitute the
rudiment of the fœtus, and which often give to the child the appearance
and dispositions of their parents. Sometimes one trait is inherited,
sometimes another; at other times a new compound or character is formed
(like a chemical union), which does not partake of the nature of either
of the former.