this from the perinaeal
centre, the prostate, C C, and base of the bladder, P, are brought into
view. The pelvic fascia may be now felt reflected from the inner surface
of the levator ani muscle to the bladder at a level corresponding with
the base of the prostate, and the neck of the bladder in front, and the
vesiculae seminales, N N, laterally. In this manner the pelvic fascia
serves to insulate the perinaeal space from the pelvic cavity. The
prostate occupies the centre of the perinaeum. If the perinaeum were to
be penetrated at a point midway between the bulb of the urethra and the
anus, and to the depth of two inches straight backwards, the instrument
would transfix the apex of the gland. Its left lobe lies directly under
the middle of the line of incision which the lithotomist makes through
the surface; a fibrous membrane forms a capsule for the gland, and
renders its surface tough and unyielding, but its proper substance is
friable, and may be lacerated or dilated with ease, after having partly
incised its fibrous envelope. The membranous part of the urethra, M,
Fig. 2, Plate 53, enters the apex of the prostate, and traverses this
part in a line, nearer to the upper than to the under surface; and that
portion of the canal which the gland surrounds, is named prostatic. The
prostate is separated from the pudic artery by the levator ani muscle,
and from the artery of the bulb, by the deep perinaeal fascia and the
muscular fibres enclosed between its two layers.

The prostate being a median structure, is formed of two lobes, united at
the median line. The bulbus urethrae being also a median structure, is
occasionally found notched in the centre, and presenting a bifid
appearance. On the base of the bladder, P, Fig. 2, Plate 53, the two
vasa deferentia, Q Q, are seen to converge from behind forwards, and
enter the base of the gland; a triangular interval is thus formed
between the vasa, narrower before than behind, and at the middle of this
place the point of the trocar is to be passed (through the rectum,) for
the purpose of evacuating the contents of the bladder, when other
measures fail. When this operation is required to be performed, the
situation of the prostate is first to be ascertained through the bowel;
and at a distance of an inch behind the posterior border of the gland,
precisely in the median line, the distended base of the bladder may be
safely punctured. If the trocar pierce the bladder at this point,