fence, repeatedly slipped back; while thus engaged, he experienced his
first seminal emission. In this way he then masturbated several
times.[31]

Let us now consider whence the ejaculated fluid can be derived prior to
the age at which it comes to contain spermatozoa. In the first place, it
is possible that the testicles themselves, before they begin to form the
spermatozoa, may yet furnish an indifferent secretion, although in the
adult the secretion of the testicles consists chiefly of the
spermatozoa. We have also to consider the glands previously enumerated,
whose secretions normally form constituents of the semen. We possess,
however, hardly any trustworthy information regarding the time at which
the glands of the vasa deferentia begin to secrete. The glands of
Cowper, as Henle[32] showed many years ago, begin to secrete within a
few weeks after birth. He believed that these glands secreted
continuously, but that the secretion was retained for a time in the
ducts, and was discharged intermittently with the urine. For this reason
he believed that the glands of Cowper did not form a part of the
reproductive system. Subsequent investigations, however, have led us to
believe that the secretion of Cowper's glands is one of the constituents
of the semen. Another constituent is the secretion of the glands of
Littre, and these glands also perhaps begin to secrete at a much earlier
age than the testicles. We may regard it as certain that the seminal
vesicles may contain secretion before any spermatozoa are formed in the
testicles. As regards the prostate gland, it is supposed that this
first begins to secrete at the commencement of the age of puberal
development or even later. According to the data collected by Frisch,
the prostate gland, comparatively small in childhood, first begins to
grow quickly at the epoch of the puberal development. During childhood,
the gland tissue is comparatively scanty, although it already contains
concretions. Only during the puberal development does the prostate gland
attain its full size; according to the researches of Englisch, who
observed 1282 instances, this does not occur until after the full
development of the testicles. Beyond question we are justified, from the
information at our disposal, in concluding that the prostate gland
begins to secrete comparatively late. But, on the other hand, it is
equally clear that certain glands whose secretion in the adult forms
part of the semen, be