n of living beings is a
demonstrated fact.

(2). The factors in evolution appear at first sight to be very
diverse: selection, mutation, climatological, physical and chemical
factors, etc.

We have seen that they may all be connected with the fundamental
principle of mnemic engraphia, aided by natural selection. No doubt
the nature of the mnemic engraphia of external agents in the living
substance is still unknown. When we are able to connect the laws of
life with the laws of inert nature, we shall only have before us a
single great metaphysical mystery, that of the tendency of mundane
energy to the differentiation of details and the production of
complicated forms. What is important here is to know that engraphia
and selection are capable of considerably modifying species in a
positive or negative manner, for good or evil, improving them by good
influence and good conjugations, or deteriorating them by bad
selection or by blastophthoria, which causes them to degenerate. The
combination of a bad selection with blastophthoric influences
constitutes the great danger for humanity, and it is here that a
rational sexual life should intervene.

(3). The mental faculties of animal species, as well as their physical
characters, depend on their ancestral hereditary mneme. They simply
represent the internal or introspective side of central activity, and
the brain obeys the natural laws of the mneme in the same way as the
other organs.

(4). It follows from all this that phylogeny and selection, the same
as heredity properly understood, have the right to a fundamental place
in the sexual question, for the germs which, after each conception,
reproduce an individual are, on the one hand, bearers of the inherited
energy of our ancestors, and on the other hand, that of future
generations. According to the care or neglect of civilized humanity
they may be transformed for good or evil, progress or recede.
Unfortunately, owing to religious and other prejudices, the question
of evolution is not discussed in schools. Hence, the majority of men
only hear of these things by hearsay in a rough and inexact manner; so
that a series of phenomena familiar to naturalists and medical men,
are still dead letters for the rest of the public. This obliges me to
speak further on some points of detail.

The so-called historical times, that is the times of the Chinese,
Egyptians and Assyrians, which appear to us extremely remote, are from
the poin