oid
depressing its handle as yet, lest its point be prematurely tilted up,
and rupture the upper side of the urethra anterior to the ligament. As
soon as the instrument has arrived at the bulb, its further progress is
liable to be arrested, from these causes:--1st, This portion of the
canal is the lowest part of its perinaeal curve, 3, 6, 8, and is closely
embraced by the middle fibres of the accelerator urinae muscle. 2nd, It
is immediately succeeded by the commencement of the membranous urethra,
which, while being naturally narrower than other parts, is also the more
usual seat of organic stricture, and is subject to spasmodic
constriction by the fibres of the compressor urethrae. 3d, The
triangular ligament is behind it, and if the urethral opening of the
ligament be not directly entered by the instrument, this will bend the
urethra against the front of that dense structure. On ascertaining these
to be the causes of resistance, the instrument is to be withdrawn a
little in the canal, so as to admit of its being readjusted for engaging
precisely the opening in the triangular ligament. As this structure, 6,
is attached to the membranous urethra, 6*, which perforates it, both
these parts may be rendered tense, by drawing the penis forwards, and
thereby the instrument may be guided towards and through the aperture.
The instrument having passed the ligament, regard is now to be paid to
the direction of the pelvic portion of the canal, which is upwards and
backwards to the vesical orifice, 3, d, 3. In order that the point of
the instrument may freely traverse the urethra in this direction, its
handle, a, requires to be depressed, b c, slowly towards the perinaeum,
and at the same time to be impelled steadily back in the line d, d,
through the pubic arch, 11. If the third lobe of the prostate happen to
be enlarged, the vesical orifice will accordingly be more elevated than
usual. In this case, it becomes necessary to depress the instrument to a
greater extent than is otherwise required, so that its point may
surmount the obstacle. But since the suspensory ligament of the penis,
10, and the perinaeal structures prevent the handle being depressed
beyond a certain degree, which is insufficient for the object to be
attained, the instrument should possess the prostatic curve, c c,
compared with c b.

[Footnote: It may be necessary for me to state that, with the exception
of this figure (which is obviously a plan, but sufficientl