As contributing to the understanding of the operations on herniæ, we shall premise a description of the parts about the testicles. The testicle itself is a glandular and friable substance, formed for the production of semen. The substances called parastatæ and cremasteres, are processes from the membrane of the spinal marrow, descending along with the arterial vessels in the testicles, by which the semen is injected into the pudendum; the spermatic vessels are veins from the vena cava passing to the testicles in a convoluted manner, and by them the testicles are nourished. The tunica vaginalis (erythroides or elytroides?) is of a nervous nature; at the convex and anterior part not adhering, but at the concave and posterior parts united to the testicle, deriving its origin from the peritoneal coat. This part, where it is united to the testicle, they call the posterior adhesion. The darti are membranes connecting the external skin to the tunica vaginalis, being united to it at the part where it is united behind to the testicle. But that wrinkled skin which forms an external covering to the testicles is called the scrotum. * * * * * COMMENTARY. Celsus gives a similar description of the parts connected with the testicles. The testicles themselves, he says, consist of medullary matter and possess no sensibility of their own, but experience violent pains and inflammations from the membrane which surrounds them. They hang from the groins by nerves called cremasters by the Greeks, with each of which descend two veins and arteries. These are covered by a thin nervous white coat, without blood, called elytroides by the Greeks. (This must be the tunica vaginalis of modern anatomists.) Above it is a stronger tunic which adheres strongly to the inner at its lower part, and is called dartos by the Greeks. (This appears to be the cremaster muscle of modern anatomists.) The veins, arteries, and nerves are surrounded by many small membranes. (By these he seems to have meant the fasciæ from the aponeurosis of the external oblique muscle.) All these parts are covered by an external investment called the scrotum. (vii, 18.) Ruffus Ephesius says that the scrotum is a loose substance in which the testicles are placed, being in particular fleshy externally; that it consists of two tunics, the external being corrugated and called dartos, and the internal being called erythroides (elytroides?). The dartos and scrotum connect the testicles to the parts above, but the erythroides (vaginalis?) is united to and surrounds the testicle itself. (De Corporis Humani partium appellationibus, ii.) Oribasius describes the cremasters as being two muscles which descend from the groins and surround the tunica vaginalis. (Anatomica ex Galeno.) (This is very similar to Cloquet’s description of them.) Theophilus’s description unfortunately has come down to us very incomplete. (De Fabricâ Hominis, v, ad finem.) SECT. LXII.—ON HYDROCELE.