as the difference between them is caused by the
fact of the serous cord remaining in part pervious in the infantile
hernia; and on comparing Fig. 6, Plate 40, with the congenital variety,
Fig. 4, Plate 40, we see that the intestine has acquired a new sac in
the former, whereas, in the latter, the intestine has entered the tunica
vaginalis. The variable position of the testicle in Figs. 4, 5, & 6,
Plate 40, is owing to the variety in the anatomical circumstances under
which these herniae have happened.

[Illustration: Abdomen and scrotum, showing bone, blood vessels
and other internal organs.]
Plate 40--Figure 6.

COMMENTARY ON PLATES 41 & 42.

DEMONSTRATIONS OF THE ORIGIN AND PROGRESS OF INGUINAL HERNIAE IN GENERAL.

PLATE 41, Fig. 1.--When the serous spermatic tube is obliterated for its
whole length between the internal ring, 1, and the top of the testicle,
13, a hernia, in order to enter the inguinal canal, 1, 4, must either
rupture the peritonaeum at the point 1, or dilate this membrane before
it in the form of a sac. [Footnote] If the peritonaeum at the point 1 be
ruptured by the intestine, this latter will enter the fibrous spermatic
tube, 2, 3, and will pass along this tube devoid of the serous sac. If,
on the other hand, the intestine dilates the serous membrane at the
point, 1, where it stretches across the internal ring, it will, on
entering the fibrous tube, (infundibuliform fascia,) be found invested
by a sac of the peritonaeum, which it dilates and pouches before itself.
As the epigastric artery, 9, bends in general along the internal border
of the ring of the fibrous tube, 2, 2, the neck of the hernial sac which
enters the ring at a point external to the artery must be external to
it, and remain so despite all further changes in the form, position, and
dimensions of the hernia. And as this hernia enters the ring at a point
anterior to the spermatic vessels, its neck must be anterior to them.
Again, if the bowel be invested by a serous sac, formed of the
peritonaeum at the point 1, the neck of such sac must intervene between
the protruding bowel and the epigastric and spermatic vessels. But if
the intestine enter the ring of the fibrous tube, 2, 2, by having
ruptured the peritonaeum at the point 1, then the naked intestine will
lie in immediate contact with these vessels.

[Footnote: Mr. Lawrence (op. cit.) remarks, "When we consider the
texture of the peritonaeum, and the mode of its connexion t