ded; but by the simple lateral incision D
being made through the forepart of the left lobe, F, these ducts will
escape injury. [Footnote] On the whole, therefore, the lateral operation
appears preferable to the bilateral one.

[Footnote: As to the mode in which the superficial and deep incisions in
lateral lithotomy should be made, a very eminent operating surgeon
remarks--"a free incision of the skin I consider a most important
feature in the operation; but beyond this the application of the knife
should, in my opinion, be extremely limited. In so far as I can
perceive, there should be no hesitation in cutting any part of the gland
which seems to offer resistance, with the exception, perhaps, of its
under surface, where the position of the seminal ducts, and other
circumstances, should deter the surgeon from using a cutting
instrument."--Wm. Fergusson, Practical Surgery, 3d Am. Ed., p. 610.]

[Illustration: Abdomen, showing blood vessels and other internal organs.]
Plate 55--Figure 1.

Fig. 2, Plate 55.--The muscular structures surrounding the membranous
urethra and the neck of the bladder, and which are divided in lithotomy,
have been examined from time to time by anatomists with more than
ordinary painstaking, owing to the circumstance that they are found
occasionally to offer, by spasmodic contraction, an obstacle to the
passage of the catheter along the urethral canal. These muscles do not
appear to exist in all subjects alike. In some, they are altogether
wanting; in others, a few of them only appear; in others, they seem to
be not naturally separable from the larger muscles which are always
present. Hence it is that the opinions of anatomists respecting their
form, character, and even their actual existence, are so conflicting,
not only against each other, but against nature. In Fig. 2, Plate 55, I
have summed together all the facts recorded concerning them, [Footnote]
and on comparing these facts with what I have myself observed, the
muscles seem to me to assume originally the form and relative position
of the parts B C D E F viewed in their totality. Each of these parts of
muscular structure arises from the ischio-pubic ramus, and is inserted
at the median line A A. They appear to me, therefore, to be muscles of
the same category, which, if all were present, would assume the serial
order of B C D E F. When one or more of them are omitted from the
series, there occurs anatomical variety, which of course oc