=The Actual Cautery.=--In some one of its improved forms the Paquelin cautery has replaced all the old cruder methods of cauterization. When properly employed its counterirritant effect can be made most serviceable for the relief of pain, or for any desired form or degree of counterirritation. Applied over the upper abdomen, with the lightest possible touch, in such a way as to deserve the term “_flying cautery_,” it will sometimes afford great relief in nausea and vomiting, especially when these symptoms are purely reflex. Used over the course of the larger nerves it does much to relieve the pain of neuritis; while over swollen joints and swollen testicles it affords great relief from the pain of chronic arthritis and chronic or acute epididymitis. In deep-seated congestions and inflammations _ignipuncture_ may be made with a small cautery point, by plunging it through the skin into the underlying tissues, and into bone. The relief of tension as well as the counterirritation will give great relief. When practised in this manner local or general anesthesia may be used. Except when thus used it will rarely be necessary to do more with it than to disturb the exterior of the skin. When skilfully used this can be done with the production of very little pain. PARACENTESIS. Paracentesis is the technical name given to the act of tapping, or the withdrawal of fluid from any of the closed cavities of the body. It includes _aspiration_, _tapping_, and _incision_. =Aspiration.=--By aspiration is meant the removal of fluid without the admission of air; it comprises the use of a suction apparatus, usually known as an aspirator, which may be had in various forms and sizes. A small so-called _exploring syringe_ will answer for small cavities, while for large collections of fluid, such as may be met with in the thorax, more elaborate apparatus is used, consisting of a suction pump connected by tubing with a bottle in which the vacuum is produced. By another tube this bottle is connected with a hollow needle used for the withdrawal of the fluid. Absolute asepsis should be observed, even in this minor procedure. The skin should be cleansed, and the needle, instrument, and hands should be sterilized. The pain of puncture may be prevented by use of the freezing spray, of cocaine injected locally, or by touching the skin with a drop of pure carbolic acid. The vacuum is commonly resorted to in the removal of fluid from the thorax, the spinal and the cranial cavities, and from joints; also in small collections of pus in any part of the body. =Tapping.=--Tapping means a somewhat similar procedure with a larger instrument known as a _trocar_ and a surrounding _cannula_, without the aid of the vacuum. Precaution should be taken in every regard that the instruments and the parts should be sterilized.