The TUNICA VAGINALIS, Fig. 184(1), was, before the descent of the testicle, a portion of the peritoneum. The testicle, while in the abdomen, is covered by the peritoneum in the same manner as the spleen or the liver, and when it descends into the scrotum carries along with it, not only the portion which adheres to its proper tunic, the tunica albuginea, but also a portion of the peritoneum which is attached to the walls of the abdomen. Hence the tunica vaginalis presents two portions, one of which is still adherent to the tunica albuginea, while the other is reflected over the inner surface of the pouch formed by the prolongation of the fascia transversalis. The latter is denominated the tunica vaginalis reflexa, and the former, the tunica vaginalis testis. They are analogous to the parietal and visceral portions of the pleura, or of the peritoneum, and, like these membranes, form a shut sac.

In studying the descent of the testicle, the student should bear in mind that it was just as much covered by the peritoneum, in the cavity of the abdomen, as it is by the tunica vaginalis, in the scrotum, and that the latter is to it in the scrotum, what the former was in the abdomen. The tunica vaginalis should be studied with reference to the occurrence of hydrocele, &c.

The TESTICLE is brought into view when the tunica vaginalis is laid open. It is of an oval form, flattened somewhat on the sides. It is about an inch and a half in length, and about three-fourths of an inch in thickness, and an inch in breadth. Its position in the scrotum is oblique, from above downwards, and from before backwards.

The EPIDIDYMIS is seen attached to its posterior border. This presents an upper large extremity, named the globus major, and a lower small one called the globus minor; the middle portion is named the body. The epididymis is partly covered by the tunica vaginalis. Having examined the exterior of the testicle, the tunica albuginea should be divided, and the glandular substance carefully removed, for the purpose of studying the structure of this tunic.

The TUNICA ALBUGINEA, Fig. 184 (2), is the proper capsule of the testicle. It is a thick, dense, white fibrous membrane. It preserves the form of this organ, and protects its delicate glandular structure. Behind, it forms a projection

internally, which is named the corpus Highmorianum, or mediastinum testis, Fig. 184 (3). From this fibrous bands pass

Fig. 184.

ginea. 3. Corpus Highmotestis. The cut ends of the vessels below the figure belong to the rete testis; those above, to the blood vessels of the testicle. 4. Tunica vasculosa of the testis. 5.

rianum or mediastinum

off in different directions to be attached at various points to the inner surface of the tunic. These add very much to the strength of the fibrous structure of the testicle, and support the vessels as they penetrate the substance of the gland. The corpus Highmorianum ist traversed by the blood vessels and nerves which enter the interior of the testicle, and, also, by convoluted seminal tubes.

It will be observed that from the dense and unyielding character of the tunica albuginea rapid effusion into the interior of the testicle would almost necessarily be attended with a great deal of pain.

The TUNICA VASCULOSA, or PIA MATER of the testicle, Fig. 184 (4), lines the internal surface of the tunica albuginea, and is reflected around the fibrous bands attached to its inner surface. It transmits the vessels to every

One of the lobules of the part of the interior of the organ.

tubuli seminiferi terminating in a vas rectum. 6. A section of the epididymis.

The GLANDULAR PORTION of the testicle consists of a great number of seminal tubes. These may be drawn. out with the forceps to the extent of a foot or more; when this is done they appear at first like exceedingly fine, delicate threads, just unravelled from a network. They adhere very slightly to each other, and may be easily separated when allowed to float in water. They are arranged in lobes of a conical shape, and of different sizes; the bases of which look forwards, and the apices backwards. There are from three to four hundred of these lobes or bundles of convoluted tubes. Some of them commence by a blind extremity, and others are joined together so as to form loops.

The TUBULI SEMINIFERI, Fig. 185 (3, 3), unite to form about twenty tubes, which are nearly straight; these enter

Fig. 185.

the corpus Highmorianum. They are termed the tubuli recti, or vasa recta. These open into the rete testis, which consists of a network of tubes, in the anterior part of the corpus Highmorianum. From the rete testis from ten to twenty tubes pass through the tunica albuginea. They are called the vasa efferentia. These are at first straight, but become convoluted, and form masses of a conical shape, which are named the coni vasculosi. These cones form the globus major or head of the epididymis, and by uniting together form a single tube, called the canal of the epididymis. This tube, after forming the body and the globus minor or tail of the epididymis, terminates in the vas deferens.

The VAS DEFERENS, Fig. 185 (10), and Fig. 186 (6, 6), commences at the lower end of the globus minor, and is directed upwards on the inner side of the epididymis. It enters the spermatic cord at the upper part of the testicle, and ascends in the posterior part of it to the internal abdominal ring, where it leaves the cord, and turning short round the epigastric artery, passes down wards and inwards over the external iliac vessels, and enters the pelvis. In the pelvis it crosses over the ureter, gets between the rectum and the bladder, and passes downwards and forwards, on the inner side of the vesicula seminalis, to the upper border of the prostate gland, where it unites with the ductus vesicula seminalis, to form the ductus ejaculatorius communis.

voluted into lobes.

4, 4.

2,2. Corpus Highmorianum. 3. 3. Tubuli seminiferi conVasa recta. 5. Rete testis. 6. Vasa efferentia. 7. Coni vasculosi constituting the globus major of the epididy

mis. 8. Body of the epididymis. 9. Its globus minor. aberrans, or blind duct.

10. Vas deferens. 11. Vas

The vas deferens is composed of an inner mucous, and an outer fibrous layer. The latter is very thick and firm, so that the tube can be distinctly felt in the spermatic cord of the living subject. The vas deferens is about two feet in length. Its size does not vary much from its commencement

OF THE PELVIS.

until it reaches the bladder, where it enlarges, and becomes sacculated.

The VAS ABERRANS, Fig. 185 (11), is a small tube which is sometimes found arising from the globus minor, or the commencement of the vas deferens, and extending a short distance upwards in the spermatic cord. It terminates in a blind extremity. Its use is not known.

Fig. 186.

The VESICULE SEMINALES, Fig. 186 (7, 7), are two sacculated bodies, situated on the base of the bladder, above the prostate gland, and in front of the rectum. They are each about two inches in length, and half an inch in breadth. They approach each other from above downwards, so as to leave a triangular space between them, in which the vasa deferentia are situated. When fully dissected out, each one is found to be from four to five inches in length. They are lined by mucous membrane, outside of which is a proper fibrous layer. They also receive a layer from the prostatic fascia, which attaches them to the bladder. Each one terminates in a short tube, the ductus vesicula seminalis.

THE POSTERIOR ASPECT OF THE MALE BLADDER; THE SEROUS COVERING IS REMOVED IN ORDER TO SHOW THE MUSCULAR COAT.-1. The body of the bladder. ferior fundus or base. 4. The urachus. 5, 5. The ureters. 6, 6.

2. Its fundus. 3. Its in

The vasa deferentia. 7, 7. The

vesiculæ seminales.

The DUCTUS EJACULATORIUS COMMUNIS, Fig. 181 (s), is about an inch in length. It passes forwards, upwards, and somewhat inwards, between the middle and lateral lobes of the prostate gland to open on the caput gallinaginis, in the floor of the prostatic portion of the urethra. At first the two ejaculatory ducts are a little distance apart, but lie close to each other in the latter part of their course. Their walls in the prostate gland are very thin, and some care is requisite to dissect them out entire.

The SPERMATIC CORD is composed of the vas deferens and the spermatic vessels and nerves. It extends from the back

part of the testicle to the internal abdominal ring. The left cord is somewhat the longest. The spermatic artery is a branch from the aorta. It enters the testicle through the corpus Highmorianum, and divides into numerous small branches, which ramify in the substance of the gland. The spermatic veins commence in the testicle, and leave it in company with the artery. Just above the testicle they form a plexus named the plexus pampiniformis. They contain no valves. Those on the right side terminate by a single trunk in the ascending cava, and those on the left side in the renal vein. The nerves of the testicle are derived from the plexus which accompanies the spermatic artery.

RELATIONS OF THE PELVIC VISCERA IN THE MALE.

The pelvic viscera of the male consist of the rectum, the bladler, the vesiculæ seminales, and the prostate gland. The rectum occupies the posterior part, and the other organs the anterior part.

In studying the relations of the RECTUM, it may be divided into two parts, the upper and lower; the first being in direct relation with the peritoneum, and the last having no serous covering.

The upper part, Fig. 187 (16), extends downwards to the recto-vesical fascia, or to within about three-quarters of an inch of the prostate gland. The whole of this part is covered in front, and partly on the sides, by the peritoneum, and is in relation with the bladder, and usually with the small intestines; the superior portion is also covered behind by peritoneum, except a small space between the lamina of the mesorectum. Below it is in apposition with the sacrum, the pyriform muscles, the branches of the internal iliac arteries, the sacral nerves, and the ureters, especially the one on the left side.

The lower part, Fig. 187 (18), is in relation behind and on the sides with the sacrum and coccyx, and the coccygeus and levatores ani muscles. It has in front of it, commencing above, first, the vesiculæ seminales and the triangular space between them on the base of the bladder; second, the prostate gland; third, the membranous portion of the urethra