It is generally supposed that the seminal vesicles serve as reservoirs for the fluid secreted by the testes, though it was the opinion the late Mr John flouter. that they perform some more active office in the animal economy.
The prostate gland is usually about as large as an ordinary chesnut, of a red colour, firm consistence, and cellular structure. It is composed chiefly of two lobes, situated principally on the lateral and dorsal parts of the neck of the bladder, thus Forming a conical body, con vex sacrad and do-sad, and flattened whin tad, so that a horizontal section of it may properly be compared to the figure of a heart on playing cards. The peripheral surface of the prostate gland is generally smooth, being covered with a membrane derived chiefly from the cel lular substance, but towards the sternal extremity are inserted the fibres of what is called the sphincter vesicl.c. The interior of the gland is cellular, and is pros ided with numerous follicles that secrete a mucous fluid, which is conveyed into the urethra by tt n or twelve ducts, opening obliquely near the termination of those canals which sue have described as coming from the seminal vesit les and coca (117 rentia.
The penis is composed principally of membranous cells, collected into three distirn t bodies, called cavern ous bodies, (corpora cavernosa,) with a membranous tube running along the dorsal or under side, and called u•t /bra. One of the spongy bodies surrounds this mem canal, and at the Ifi•'a extremity of the petik, expands into cc hat is called the glans pe xis. This col lection of cells is called by anatomists cc/,us urethra.. The others firem the sides and an rral or up per part of the penis, and are called car rrosa Each of these spongy bodies is separated from the rest by a distinct inveloping membrane, so that it is pos-lble to till the cells of the spongy cavernous bodies of the penis, while those of the urethra remain empty, and vice versa. The corpora cavernosa PC7liS are divi ded from each other by a membranous partition, run ni..g longitudinally du ough the middle of die penis, as fat as the root of the glans; but this partition is said not to afford a complete separation between the corpora cart 'masa, which therefore communicate with each other attots part. See Fy fe's Compendium of .Inatomy, 3d
edit. vol. ii. p. '235. The cavernous bodies of the penis, arise by two conical extremities called (Tura, from the menial side of the ischia and pubes, and are connected with these bones by ligaments. They unite at the sa cral part of the symphystspubis..* The penis is supplied with three principal arteries on each side, coming from the pudic arteries. Its veins are numerous, and most of them terminate in one large trunk, called the great or dorsal vein of the penis, which runs along the sternal side of that organ, in a groove between the two cavernous bodies. The penis is furnished with large nerves, and has numerous lym phatics.
There are two muscles belonging to this organ, one on each side, attached to the membrane that covers the cavernous bodies near their union, and to the menial side of the tuberosity of the ischium. These are called erectores penis, because when they contract, they press on the cells of the cavernous bodies, and thus favour the distension of that organ.
The membranous canal, called urethra, runs from the neck of the bladder to the distal extremity of the penis. It is nearly cylindrical in its different parts, though it is not of the same diameter through its whole extent. It is largest at about an inch distad from the prostate gland, where there is also an enlargement of its peri pheral spongy part, constituting what is called the bulb of the urethra. There is another dilatation at the pros tate gland, and a third near the root of the glans penis. The rest of the canal is about as large as an ordinary goose quill. Between the prostate gland and the prox imal part of the bulb, the urethra is entirely membra nous, being surrounded only by loose cellular substance, but the remainder of the canal is surrounded by the spongy body. Along the middle of the peripheral sur face of the bulb there is a tendinous line, from which numerous muscular fibres run obliquely towards the sphincter ani and cram of the cavernous bodies of the penis. These fibres form too small muscles which are the acceleratores twins, or ejaculatores Nrminis of anato mical writers.