The notion that the cure of hydrocele depends on promoting adhesion to the sides of the tunica vaginalis with the testicle is somewhat upset by several preparations in the London hospitals, exhibiting the _tunic_ taken from persons in whom a radical cure was effected by injection, and in whom no fluid was reproduced; nor were the sides of the said investment at all adherent with the testicle, but apart, as in the healthiest individual. Hitherto surgeons, acting on the aforesaid notion, with a view to obliterate the cavity, adopted various plans of treatment—such as, for instance, laying open the entire cavity, cutting away a portion of the tunica vaginalis, the application of caustic, and, lastly, the seton, as advised by Dr. Pott, which was suffered to liberate itself by ulceration. When, in any of these instances, suppuration was induced, the cavity became in time filled up by the granulating process. The plan of the present day is by perforating the sac with a trocar, suffering the effused fluid to escape, and injecting some stimulating liquid which is allowed to remain until a degree of inflammation is produced, that shall cause an obliteration of the cavity by adhesion, or, as it has also been proved, prevent a reproduction of the fluid, by closing the mouths or altering the diseased action of the exhalent arteries. Whichever be the effect produced thereby, the cure is almost certain, and the principles of the treatment consequently judicious. But, notwithstanding, the operation is not always immediately, nor _ultimately_ successful; the degree of inflammation set up may be insufficient, and the effusion again take place, and the operation may require a second and third repetition; or an excessive degree of inflammation may ensue, that shall occasion serious constitutional disturbance, either by suffering the injected fluid to remain too long, or its being of too stimulative a character, or from its escaping into the cellular membrane of the scrotum, an accident not unfrequent, unless great care be used in the operation. _Radical Cure of Hydrocele._—The term radical is applied to the process narrated in the last case; but, as has been observed, the operation is occasionally required to be repeated several times. In the case I am adverting to, after tapping, several injections were thrown in between the tunics, and withdrawn; and on one occasion the morbid fluid was secreted to the greatest possible distension of the scrotum by the following morning. Its subsequent withdrawal, and the injection of a more active stimulant, effected, however, a permanent cure. In the country, surgeons frequently plunge a lancet in the scrotum, suffer the effused liquid to escape, and desire the patient merely to wrap the parts up in a handkerchief, to take no further heed, and to ride home: and these cases generally do well.