ete the substance which they contain, no part
of the secretion of the testes normally finding its way into the
vesicles._

_The prostate gland, a portion of which is homologous with the female
uterus and called uterus masculinus_, is situated around the neck of
the bladder and is traversed not only by the urethra (prostatic
portion), but also by the ejaculatory ducts. There are numerous gland
ducts which--collecting the secretion of the prostate gland--open into
the urethra in the prostatic portion.

Just beyond the prostate are two small glands called _Cowper's Glands_
whose ducts enter the urethra some distance beyond the prostate, at
the root of the penis.

2. PHYSIOLOGY.

In the treatment of the physiology of the various structures just
described, we may well reverse the order of treatment, thus leading up
step by step to a consideration of the more important organs.

a. =Urethra.= The canal or duct of the penis is called the urethra,
and it is important in considering its physiology to remember that it
has not only a double function to perform, but that the performance of
one function in a measure temporarily unfits it for performance of the
other and makes it necessary for a special measure of preparation.

The urinary excretion from the kidneys collecting in the urinary
bladder is passed out periodically through the urethra. This same
channel must transmit periodically secretions from the sexual
apparatus.

b. =Cowper's Glands= secrete only under sexual excitement, and usually
they secrete only when the sexual excitement reaches a stage which
induces an erection. The secretion is composed of a clear _alkaline
mucus_.

The purpose served in the natural economy by this alkaline mucus is a
very important one and it is essential that every young man should
understand it.

It will be remembered that the male urethra affords passage not only
for the urine, but also for the generative products. The urine is
acid in reaction and the frequent passage of urine along the urethra
leaves that duct acid in reaction under usual conditions. The
spermatozoa are very sensitive to acid and their vitality is seriously
impaired by acid of any kind, particularly the acid of the urine.
Nature has provided that the secretion from Cowper's glands should
precede the generative products along the urethra, thus neutralizing
the acid and insuring for the spermatozoa an alkaline passage from the
body.

Besides this important