An inert fluid, collected about the parts which are enveloped by the scrotum, and occasioning a marked swelling there, has obtained this appellation. The fluid is, for the most part, collected in the tunica vaginalis around the testicle, at its anterior part; but the affection is sometimes, though rarely, formed externally to the tunica vaginalis. Often, however, it is collected in the proper tunic of the testicles, and surgeons call this affection hydrocele of the tunica adnata. If the complaint is formed from some preceding cause, such as weakness of the parts, the blood brought there for the purpose of nourishment is converted into an inert watery or serous substance. But if it is occasioned by a blow, a sanguineous or feculent substance constitutes its contents. The common symptom is a permanent swelling without pain about the scrotum, not disappearing under any circumstances, yet somewhat compressible when the collection is small, but not at all compressible when it is large. When the fluid is collected in the tunica vaginalis the swelling is globular, but somewhat oblong like an egg; and in these cases the testicle is not to be felt as being everywhere surrounded with the fluid. But that which is collected externally to the tunica vaginalis, is felt as through a small intervening substance. When it is formed in the adnata, being everywhere circumscribed and globular, the swelling has the appearance of another testicle. If the fluid be watery, the swelling is of one colour and transparent; but if it be feculent and bloody, it appears red or livid; and if these symptoms appear in both parts of the scrotum, you may be sure that there is a double hernia. We operate upon it in this manner. Having shaven the pubes and scrotum, unless the patient be a boy, we lay him in a supine posture upon a bench, and apply to his buttocks a cloth several times folded, and to the scrotum a sponge of considerable magnitude, and sitting at the left side of the patient, we give directions to an assistant sitting at his right side to draw the genital organs to the other side, and to draw up the skin of the scrotum to the abdomen. Then taking a scalpel we divide the scrotum longitudinally from its middle to near the pubes, making the incision straight and parallel to the raphe which divides the scrotum into two parts, and extending the incision down to the vaginalis. When the fluid is in the adnata, we make the incision where the apex of the tunica adnata makes its appearance, and separating the lips of the incision with a hook, and having dissected the darti with a knife for hydrocele and a scalpel, and laid bare the tunica vaginalis, we divide it through the middle with a lancet for bleeding, more especially in that part where it is separated from the testicle; and having discharged into some vessel the whole or most of the fluid, we cut away the vaginalis, especially its thinnest parts, with hooks. Afterwards, Antyllus uses sutures and