So common are small cysts connected with the epididymis in the various states and stages I have described, that it is impossible to examine many testicles, especially of persons beyond the age of puberty, without finding them. According to M. Gosselin t, they are liable to be developed from the period of puberty to the age of thirty or thirty-five, but are rare at this period. After the age of forty. they are very common, having been met with by him in at least two thirds of the testicles examined. Now when one or more of these cysts, instead of becoming pedunculated, en large so as to form a tumour in the scrotum they constitute the form of hydrocele, called from its original seat, encysted hydrocele of the epididymis. I have observed this description of hydrocele in all its various modifications, from the enlargement simply of a single cyst to the complication occasioned by the varied de velopment of several. As a cyst enlarges the epididymis becomes flattened, and displaced to one side, whilst the testicle is found either in front or at the bottom. It is sometimes at the side, but rarely at the posterior part of the swelling.
In the above woodcut (fig. 640.) of a spe cimen in the London Hospital Museum, the cyst is above the testicle, which is so dis placed by it that its anterior edge is directed downwards. The tumour is generally of smaller size than a simple hydrocele, the fluid commonly not exceeding three or four ounces in quantity. I have, however, removed as much as thirty-two ounces from a single cyst. When the hydrocele is composed of several cysts, they are seldom of large size, but form a cluster more or less complicated and irre gular, according to their size and number.
A curious sacculated arrangement produced by the development of numerous contiguous cysts may be seen in the annexed figure, (fig. 641.) taken from a preparation dissected by are naturally closely adherent to each other. This is a very rare form of hydrocele. A spe cimen which I discovered accidentally in dis section, is represented in the annexed wood cut. (fig. 642.) The cyst contained about two myself: part of the walls of the cysts are cut away to exhibit their interiors. The cysts are liable to inflammation, which causes more or less alteration in the quality and appearance of the fluid contained in them. The fluid may become albuminous and assume the straw or amber colour of ordinary hydrocele; and the cyst may contain lymph, form adhesions, or be lined with a false membrane, the fluid being thick and turbid. The cysts sometimes also become filled with blood, constituting a variety of hiematocele.
2. A cyst may form between the tunica albuginea and the visceral layer of the tunica vaginalis, separating the two membranes which drachms of fluid, and is situated along the front of the testicle ; it is a little thickened. A sec tion of it is preserved in the Hunterian Museum. Sir B. Brodie has described a very similar specimen.* In the museum of St. Thomas's Hospital there is a specimen of a small cyst apparently developed from the epididymis : in its subsequent growth it had extended on the fore-part of the testicle, separating the tunica vaginalis from the tunica albuginea.
r 3. In examining a healthy testicle I once found six or seven small cysts about the size of currants, studding the surface of the loose portion of the tunica vaginalis. Two of them were situated in a part of the membrane ex tending tip the cord. They projected in ternally, and contained a limpid fluid. I have twice since seen a similar kind of cyst in the same portion of the tunica vaginalis. Similar adventitious cysts have also been observed on the internal surface of the sac of a simple hydrocele, and a preparation of the kind is contained in the Hunterian Museum. If a cyst developed in this membrane were to increase to any size, it would constitute a swelling which might be appropriately termed an encysted hydrocole of the tunica vaginalis.
A circumstance of much interest in con nection with encysted hydrocele of the tes ticle, is the occurrence of spermotozoa in the fluid contents of the cyst, a discovery made by the late Mr. Liston in 1843. During the last six years I have met with them in as many as twenty cases of encysted hydrocele : indeed, in the majority of instances in which I have searched for them. They were found in subjects of various ages from 30 to 75, and in cysts of all sizes from that of a filbert to the largest which the hydrocele attains. The fluid in some instances contained these bodies in remarkable abundance; in others they existed sparingly. When very numerous, they give to the fluid an opaline opacity, or an appear ance resembling cocoa-nut milk which is so characteristic as to enable the surgeon to pre dicate their presence from the appearance of the fluid alone without minute examination. If the fluid be allowed to remain at rest in a glass vessel, the spermatozoa subside to the bottom, rendering the lower portion more opaque than the upper. The fluid also ex hibits slight traces of albumen, when tested in the usual way, which is not the case with the ordinary pellucid colourless fluid of encysted hydrocele. The spermatozoa were often as lively as in fresh semen. They were observed more frequently in the larger cysts than in the smaller. I once found them in fluids removed from two distinct cysts connected with the epididymis of a man about sixty years of age. 1 have detected them in the fluid from en cysted hydroceles tapped for the first time, and also in the examination of small cysts connected with testicles removed after death. I removed from an old man aged 75, who had had encysted hydrocele for eight years, and which had never been tapped before, as much as thirty-two ounces of fluid, which contained an abundance of spermatozoa. They were also detected in fluid taken from a man aged 54, who stated that the tumour had existed for eight years, and had never been operated on.