secondly, to cherish and nourish it, until Nature has fully formed the
child, and brought it to perfection, and then it operates strongly in
expelling the child, when the time of its remaining has expired,
becoming dilated in an extraordinary manner and so perfectly removed
from the senses that they cannot injuriously affect it, retaining within
itself a power and strength to eject the foetus, unless it be rendered
deficient by any accident; and in such a case remedies must be applied
by skilful hands to strengthen it, and enable it to perform its
functions; directions for which will be given in the second book.

The use of the preparing vessels is this; the arteries convey the blood
to the testicles; some part of it is absorbed in nourishing them, and in
the production of these little bladders (which resemble eggs in every
particular), through which the _vasa preparantia_ run, and which are
absorbed in them; and the function of the veins is to bring back
whatever blood remains from the above mentioned use. The vessels of this
kind are much shorter in women than in men, because they are nearer to
the testicles; this defect is, however, made good by the many intricate
windings to which those vessels are subject; for they divide themselves
into two branches of different size in the middle and the larger one
passes to the testicles.

The stones in women are very useful, for where they are defective, the
work of generation is at an end. For though those bladders which are on
the outer surface contain no seed, as the followers of Galen and
Hippocrates wrongly believed, yet they contain several eggs, generally
twenty in each testicle; one of which being impregnated by the animated
part of the man's seed in the act of copulation, descends through the
oviducts into the womb, and thus in due course of time becomes a living
child.