—These are connected with the urachus, which should ordinarily be found as a fibrous cord, but which occasionally persists in a pervious condition, in whole or in part. At birth it is often traversed by a narrow canal lined with epithelium continuous with that of the bladder. The urachus lies outside the peritoneum, and may be dilated at any point between its two extremities. When the entire urachus is pervious urine is discharged from the navel.
3. Cysts Connected with Remains of the Wolffian Body.
—The Wolffian body, or the mesonephros, is intimately related with the development of the kidney, the ovary, and the testis. In the two latter locations glandular elements may be met, persisting in adult life.
In the male the tubules persist as excretory ducts from the testis, but in the female they persist, in a vestigial condition, as the parovarium and Gärtner’s ducts. The ovary proper consists of the oöphoron and the paroöphoron, the former being the egg-bearing portion, the latter receiving the tubules from the adjoining structure known as the parovarium. The paroöphoron gives rise to cysts which burrow deeply between the layers of the broad ligament, make their way alongside the uterus, and raise the peritoneum. It is a peculiarity of these cysts that their inner walls often become papillomatous, and may even develop such a crop of warty outgrowths that these make their way through the cyst wall and protrude into the abdominal cavity, where they sometimes become detached and are dropped as loose bodies into the peritoneal sac. The condition is also often accompanied by warty growths upon the peritoneal surfaces. These need give rise to no alarm, because they usually disappear spontaneously with removal of the tumor. Paroöphoritic cysts are to be distinguished from parovarian cysts, which develop from the parovarium, this latter consisting of a number of tubules situated between the layers of the mesosalpinx, composed of an outer series known as Kobelt’s, an inner set, about a dozen in number, known as the vertical tubules, with a straight tube, running at right angles to these through the broad ligament to the vagina, known as Gärtner’s duct, which is homologous with the vas deferens in the male. Cystic dilatation of Kobelt’s tubes is often seen, these cysts being very small and having no clinical importance. Cysts arising from the vertical tubules are usually transparent until they attain considerable size, when their walls thicken. Their contained fluid is not harmful, and after rupture of such cysts internally the fluid is absorbed. Such cysts may rupture and refill several times. As between the paroöphorous and parovarian cysts the latter are easily enucleated, carry the ovary upon one side, and have the Fallopian tube stretched over them without communication.
The internal sections of Gärtner’s duct are more often involved in animals than in women, but excellent illustrations of cystic dilatation of its various portions have been observed, usually in the walls of the vagina.
Corresponding to the above-mentioned conditions in the female there are in the male, as the result of changes in the Wolffian body, two conditions—encysted hydrocele of the testicle, and general cystic degeneration of the same. Like the ovary, the testicle is a complex organ with remnants of the mesonephros persisting among its ducts, while only a few of the Wolffian tubules remain. True encysted hydroceles arise sometimes in the efferent tubes of the testis and sometimes in Kobelt’s tubes (the same structures which in the female give rise to parovarian cysts), the two conditions, therefore, being analogous and homologous. These cysts, though closely associated with the testis, lie outside its tunica vaginalis. Their contained fluid is usually clear or of a milky whiteness, due to fat globules. Sometimes it contains spermatozoa. Another variety is cystic dilatation of one or more of Kobelt’s tubules, which is often described as involving the hydatid of Morgagni.
General cystic disease of the testis, known also as adenomatous degeneration, was formerly referred to as hydatid disease of the same organ. The multiple cysts appear to originate in the remnant of the mesonephros still persisting, known as the paradidymis. The cavities are lined with epithelium, and papillomatous intracystic formation is not uncommon. These tumors have been called by a number of improper names, such as “cystic sarcoma,” etc.
Hydroceles.
—The term hydrocele has covered numerous conditions. At present, when no other locality is designated, hydrocele of the tunica vaginalis is understood. (The term implies a collection of watery fluid in a previously existing serous cavity.) This is the most common form.
Possibility of its formation depends upon the prolongation of the peritoneal cavity which takes place in advance of or along with the descending testicle, and which in many of the lower animals remains connected with the general cavity throughout life. In men only is it expected to close, even before birth. When the portion which extends along the spermatic cord is not completely obliterated there is encysted hydrocele of the cord, or funicular hydrocele, which is not common. The common form of hydrocele is constituted by serous effusion into the tunica vaginalis, and occurs usually without recognizable exciting cause. It will be treated more fully in its appropriate place.