(From injicio, to throw into). An injection, called also eisbole. Fluids used for injection should be used lukewarm; and may be applied either by a syringe or clyster pipe.

When used in gleets or gonorrhoeas, Dr. Swediar advises that the syringe should have a short but wide pipe, so large that its orifice may enter the urethra, and the piston be close to its sides. If the whole pipe of the syringe be much smaller than the orifice of the urethra, it may wound the inside of the canal, and admit the poison by absorption, or the liquid run out sideways, instead of passing into the urethra. If the piston itself does not apply closely to the sides of the syringe, even if the pipe is sufficiently large, so that it perfectly closes the orifice of the urethra, the liquor will still regurgitate between the piston and the syringe, and very little of the fluid will pass. The syringe being properly made, should be applied closely and exactly to the orifice of the urethra; so that, by the conic form of its pipe, all passage may be denied to the liquid betwixt it and the sides of the urethra. If the disorder lies in the usual original seat of gonorrhoeas, viz. just under the fraenum, the patient should, with one hand, compress the urethra at the first curvature of the penis, where the scrotum begins, while he holds and manages the syringe with the fingers of the other. The piston, which should always go close and easy, ought then to be pressed softly and slowly, till he feels the urethra gently dilated, and thus keep the liquid injected for a minute or two in the passage, repeating the same operation three or four times. By a rash or longer continued pressure of the piston, the irritation often does considerable injury. By attending to these directions, the liquid is properly applied to the part affected, and no dinger is incurred of carrying some of the venereal poison farther into the urethra with the injected liquid. This precaution is, however, not very necessary, as the dilution will prevent any injury. The liquid should always, in cases of virulent gonorrhoea, be lukewarm; but in gleets, cold. In gonorrhoeas, if the liquid is too cold or too warm, it is supposed likely to hurt the patient, either by the retropulsion of the matter, or increasing the inflammation. In all cases, before an injection is applied, the patient should attempt to' make water. There are a variety of injections made use of in this complaint; among the most efficacious are the following:

Injection of acetated ammonia. To three ounces of distilled water add one ounce of acetated ammonia. - Of Acetated Litharge. To four ounces of rose water add eight drops of acetated litharge. - Muriated injection. To four ounces of distilled water add eight drops of muriatic acid. - Oily injection. To four ounces of oil of almonds add eight drops of acetated litharge. - Opiate injection. To four ounces of distilled water add forty or sixty drops of tincture of opium. - Injection of green tea.

Infuse half an ounce of green tea in four ounces of boiling water, and let it stand till cold. - Compound injection of cerussa, see Plumbum. - Injection of muriated quicksilver. To four ounces of distilled water add two drops of the liquor of muriated quicksilver. This must be weakened if the inflammation in gonorrhoea is great: or, should there not be any, it may be strengthened. Any of these may be used in the inflammatory stage of a gonorrhoea; but the muriated is considered as the most eligible, where the scalding of urine is very troublesome. - Injections of vitriol of zinc. Dissolve ten grains of vitriol of zinc in five ounces of water. - Compound injections of vitriol of zinc. Add to the above ten drops of acetum lythargyri, or half a drachm of white vitriol, with as much acetated lead,adrachm of camphor, and two scruples of opium, are dissolved in sixteen ounces of boiling water, and strained. - Mercurial injections. Mucilaginis gum arab. iv. calomelanos 3 ss. or hydrargyri purificati 3 i. mucilaginis iss. aq.

iss. As astringent injections the following are recommended: injection of alum. Dissolve four" grains of alum in four ounces of rose water. - Of copaiba. Mix two drachms of balsam of copaiba with six ounces of rose water, by means of the yolk of an egg; or, with four ounces of lime water, by means of the mucilage of gum arabic; of acetated copper; of ammoniated copper; of vitriolated copper; compound injection of vitriolated copper. (See Cuprum.) These arc beneficial in the last stage of gonorrhoea; gleets; fluor albus; and, perhaps, with small portions of their active ingredients may be employed in the inflammatory stage as sedatives. Injec- . tion of galls. See Gallae.

Patients who labour under gleets, after having used injections with some advantage, grow careless in the application, and even sometimes neglect them for a day or two. The consequence of this has been that the discharge has increased, as if it had been a fresh disease; and the relapse being more obstinate than the original complaint, the patients have been obliged to continue the injections for more weeks than it might have required days had their use not been interrupted. In general, to prevent all danger of a relapse, it is proper to employ the injections three, four, or, according to circumstances, six times a day during the disease, and to continue the same regularly for ten or twelve days after the running has entirely ceased.

In anatomy great improvement hath been made by means of injections. Ruysch first employed them with success; and it is said that the Czar Peter, seeing an injected boy, whose appearance nearly resembled life, ran and kissed it.

Injections, which unite with water, and consequently with the animal fluids, consist of isinglass and common glue. These succeed with the finer vessels, in membranes; but, if employed to fill the larger, they take too long time in coagulating. If coagulated by alcohol, they become brittle; and, when the water is carried off by evaporation, the vessels are not properly filled. It has been attempted to remove these inconveniences, by first injecting the solution of glue; and, when the capillary vessels are filled, a coarser wax injection; but the wax either hardens too soon, mixes irregularly with glue, or the parts separate where the two fluids are in contact.