modern world in this matter
and determine the ideas of purity that surround us.

At the present day the crude theory of the sexual impulse held on one
side, and the ignorant rejection of theory altogether on the other side,
are beginning to be seen as both alike unjustified. We begin to find the
grounds for a sounder theory. Not indeed that the problems of sex, which
go so deeply into the whole personal and social life, can ever be settled
exclusively upon physiological grounds. But we have done much to prepare
even the loftiest Building of Love when we have attained a clear view of
its biological basis.

The progress of chemico-physiological research during recent years has now
brought us to new ground for our building. Indeed the image might well be
changed altogether, and it might be said that science has entirely
transferred the drama of reproduction to a new stage with new actors.
Therewith the immense emphasis placed on excretion, and the inevitable
reaction that emphasis aroused, both alike disappear. The sexual
protagonists are no longer at the surface but within the most secret
recesses of the organism, and they appear to science under the name of
Hormones or Internal Secretions, always at work within and never
themselves condescending to appear at all. Those products of the sexual
glands which in both sexes are cast out of the body, and at an immature
stage of knowledge appeared to be excretions, are of primary reproductive
importance, but, as regards the sexual constitution of the individual,
they are of far less importance than the internal secretions of these very
same glands. It is, however, by no means only the specifically sexual
glands which thus exert a sexual influence within the organism. Other
glands in the brain, the throat, and the abdomen,--such as the thyroid and
the adrenals,--are also elaborating fermentative secretions to throw into
the system. Their mutual play is so elaborate that it is only beginning
to be understood. Some internal secretions stimulate, others inhibit, and
the same secretions may under different conditions do either. This fact is
the source of many degrees and varieties of energy and formative power in
the organism. Taken altogether, the internal secretions are the forces
which build up the man's and woman's distinctively sexual constitution:
the special disposition and growth of hair, the relative development of
breasts and pelvis, the characteristic differences in motor