Schleich's method. Closely allied to the method of subcutaneous medication is the plan of inducing anæsthesia by injection into the skin itself, so as to obtain the pressure of the fluid on the nerve endings and the local action of the anodynes simultaneously. The agents employed for this purpose are cocaine, morphine, and common salt—the last method being used because of its physical properties. Some of the newer anodynes, especially eucaine "a" and "b," have lately been proposed as substitutes for cocaine, but the most recent researches have shown that cocaine is in all respects the most desirable for the production of local anæsthesia. Of course, the principle of this method is to procure the most effect with the least expenditure of material. Various formulae are to be found on page 611. To avoid untoward results, the solution must be weak, for such a number of punctures is made as the seat of pain or the length of the incision may require. The fluid injected must be sufficient in amount to cause a wheal to arise at that point, and they must be numerous enough to render the whole surface to be operated on entirely anaesthetic. It must not be forgotten that the point of the needle is passed into, and not through, the true skin, if the operative procedure is to be confined to this tissue. When the desired area of skin is rendered anaesthetic the fluid can then be injected into the subcutaneous areolar tissue, and into the deeper parts exposed in the course of a surgical operation. When thus inserted into the skin an incision can be made without pain, a small tumor removed, an abscess opened, or a small amputation practiced. The same method is applicable to the treatment of neuralgia, or to allay the pain of a local inflammation. When the skin which it is intended to incise is the seat of an acute hyperæmia or inflammation, the infiltration anaesthesia is practiced around or about the part, and this is not acted on until the sensibility is so far reduced that the injection into the true skin can be practiced without suffering.

Instead of solutions prepared for use, it is preferable to make use of powders containing right proportions of the several ingredients. They can be dissolved in rain, filtered, or distilled water, made sterile by boiling at the time required. A conspicuous advantage of the method is the small quantity of the anodyne required. Cocaine anaesthesia practiced in the ordinary way is not without danger; but by this method the result is more perfectly accomplished, and the danger is not appreciable