f stricture, and it certainly is so; but
never from a cause originating in itself per se, or independently of
adjacent structures. The form of the sac of a hernia is influenced by
the parts through which it passes, or which it pushes and elongates
before itself. Its neck, H, Plate 37, is narrow at the internal ring of
the fascia transversalis, because this ring is itself narrowed; it is
again narrowed at the external ring, T, Plate 36, from the same cause.
The neck of the sac of a direct hernia, I, Plate 37, being formed in the
space of the separated fibres of the conjoined tendon, or the pubic part
of the transversalis fascia, while the sac itself passes through the
resisting tendinous external ring, is equal to the capacities of these
outlets. But if these constricting outlets did not exist, the neck of
the sac would be also wanting. When, however, the neck of the sac has
existed in the embrace of these constricting parts for a considerable
period--when it suffers inflammation and undergoes chronic
thickening--then, even though we liberate the stricture of the internal
ring or the external, the neck of the sac will be found to maintain its
narrow diameter, and to have become itself a real seat of stricture. It
is in cases of this latter kind of stricture that experience has
demonstrated the necessity of opening the sac (a proceeding otherwise
not only needless, but objectionable) and dividing its constricted neck.

The fact that the stricture may be seated in the neck of the sac
independent of the internal ring, and also that the duplicature of the
contained bowel may be adherent to the neck or other part of the
interior, or that firm bands of false membrane may exist so as to
constrict the bowel within the sac, are circumstances which require that
this should be opened, and the state of its contained parts examined,
prior to the replacement of the bowel in the abdomen. If the bowel were
adherent to the neck of the sac, we might, when trying to reduce it by
the taxis, produce visceral invagination; or while the stricture is in
the neck of the sac, if we were to return this and its contents en masse
(the "reduction en bloc") into the abdomen, it is obvious that the bowel
would be still in a state of strangulation, though free of the internal
ring or other opening in the inguinal wall.

The operation for the division of the stricture by the knife is
conducted in the following way: an incision is to be made through the