ernal and serous. By the
first, he means, I presume, that membrane of which the transversalis and
iliac fasciae are parts. (See Comment. de Periton. Structura, &c.) ]

[Illustration: Abdomen and leg, showing blood vessels, muscles
and other internal organs.]
Plate 39--Figure 1

PLATE 39, Fig. 2.--The testicle in the scrotum.--When the testicle, 5,
descends into the scrotum, 7, which happens in general at the time of
birth, the abdomino-scrotal fibro-serous membrane, 6 a, 6 d, is still
continuous at the internal ring, 6 b. From this point downwards, to a
level with the upper border of the testicle, the canal of communication
between the scrotal cavity and the abdomen becomes elongated and
somewhat constricted. At this part, the canal itself consists, like the
abdominal membrane above and the scrotal membrane below, of a fibrous
and serous layer, the latter enclosed within the former. The serous
lining of this canal is destined to be obliterated, while the outer
fibrous membrane is designed to remain in its primitive condition. When
the serous canal contracts and degenerates to the form of a simple cord,
it leaves the fibrous canal still continuous above with the fibrous
membrane (transversalis fascia) of the abdomen, and below with the
fibrous envelope (tunica albuginea) of the testis; and at the adult
period, this fibrous canal is known as the internal spermatic sheath, or
infundibuliform fascia enclosing the remains of the serous canal,
together with the spermatic vessels, &c.

[Illustration: Abdomen and scrotum, showing bone, blood vessels
and other internal organs.]
Plate 39--Figure 2

PLATE 39, Fig. 3.--The serous tunica vaginalis is separated from the
peritonaeum.--When the testicle, 7, has descended to the scrotum, the
serous tube or lining of the inguinal canal and cord, 6 b, 6 c, closes
and degenerates into a simple cord, (infantile spermatic cord,) and
thereby the peritonaeal sac, 6 a, becomes distinct from the serous
tunica vaginalis, 6 d. But the fibrous tube, or outer envelope of the
inguinal canal, remains still pervious, and continues in this condition
throughout life. In the adult, we recognise this fibrous tube as the
infundibuliform fascia of the cord, or as forming the fascia propria of
an external inguinal hernia. The anterior part of the fibrous spermatic
tube descends from the fascia transversalis; the posterior part is
continuous with the fascia iliaca. In relation to the testicle, the