When the quantity of the medicament to be used hypodermatically is sufficient in bulk, the most convenient mode of procedure is to prepare extemporaneous solutions from powders or compressed tablets of definite weight. Experience has abundantly proved that clean river, cistern, spring, or well water, is better than distilled water for preparing solutions. If not very recently distilled, the water soon becomes turbid from the development in it of a minute vegetable organism—a penicillium—which grows at the expense of the alkaloid, and thus as it increases in impurity also lessens in strength. The antiseptics—such as carbolic acid, chloroform, salicylic acid, cherry laurel, etc.—do not succeed in preventing the development of the parasite for any considerable period unless added to the solution in such quantity as to render it very irritating. The least objectionable, and at the same time the most effective comparatively, is chloroform-water (aqua chloroformi), which is made by saturating freshly-distilled water with chloroform, about two minims being required for the ounce. Oil of vaseline is also an efficient solvent for many active principles, and is free from irritating qualities. Heating the water to the boiling point is also a highly useful expedient, for this temperature is sufficient to kill the organism referred to, and to render innocuous any organic matter present.

"Hypodermic tablets," as they are designated, are now made by the manufacturing pharmacists on an extensive scale. They have the advantage of permanence of form, solubility, and accuracy of dose. When very minute doses are required, a vehicle becomes necessary. Some manufacturers use beet-root sugar for the purpose ; others, sulphate of soda ; but the latter is the more commendable because it is soluble, and undergoes no change. Sugar, although soluble, has the serious disadvantage that it is liable to decomposition, and thus to produce local troubles.

Morphina

Morphine. Rx Morphinae sulphat., gr. xvj ; aquae, vel aquae chloroformi, oz j. M. Sig. : Two (2) minims are equal to one-fifteenth of a grain.

An antiseptic solution of morphine, intended to be kept for several weeks, may be prepared according to the following formula :

Rx Morphinae sulph., gr. xvj; acid, carbolic, gtt. v; aquae, ozj. M. Sig.: Two minims contain 1/15 of a grain of sulphate of morphine.

Solutions of morphine may be readily prepared extemporaneously from powders or pellets of a definite strength, as follows :

Rx Morphinae sulphat., 3j; atropinae sulphat., gr. ss. M. ft. pulv. no. cxx (120). Sig. : Each powder contains 1/6 of a grain of morphine and 1/240 grain of atropine.

Atropina. Atropine

Atropine. Rx Atropinae sulphat., gr. ij ; aquae, oz j. M. Sig. : One minim contains 1/240 of a grain. Three (3) minims contain fa of a grain, which is a maximum dose for many persons.

Morphina and Atropina

Rx Morphinae sulphat., gr. xvj ; atropinae sulphat., gr. ss. ; aquae, vel aquae chloroformi, oz j. Μ. Sig. : Six (6) minims contain 1/3 grain of morphine and 1/160 grain of atropine.

Cocaina

Cocaine. Rx Cocainae hydrochlor., gr. xxiv; aquae, vel aquae chloroformi, oz j. Μ. Sig. : One grain to 20 minims.

Urethan Rx

Rx Urethan, 3j; aquae, ozj. M. Sig.: Each drachm contains 7½ grains.

Duroisina

Duboisine. Rx Duboisinae sulphat., gr. j ; aquae, oz j. M. Sig.: Four (4) minims contain 1/120 grain. Eight minims is the usual maximum dose for an adult.

Hyoscyamina

Hyoscyamine. Rx Hyoscyaminae sulph. vel hydrobromat., gr. j ; aquae oz j. M. Sig. : Five (5) minims contain -fa grain.

Hyoscine, the other alkaloid of hyoscyamus, is the better hypnotic. The following solution may be used :

Rx Hyoscinae hydrobromat., gr. j ; aquae destil., oz ss. M. Four minims contain 1/60 grain.

Strychnina

Strychnine. Rx Strychninae sulphat., gr. j; aquae, oz j. M. Sig. : Ten (10) minims contain fa of a grain.

Conina

Conine. Rx Coninae hydrobromat., gr. j; aquae, ozj. M. Sig.: Ten (10) minims contain fa of a grain.

Curara

or Woorara. Rx Ourarae, gr. j; acid, acetic, Mv; aquae, ad τη c (to 100 minims). M. Filter. Sig. : Ten (10) minims contain 1/10 of a grain.

As the active constituents of curara are soluble in water, an aqueous solution will contain them—the residue being woody fiber, starch-granules, etc. As, however, the specimens vary greatly in strength, the character of any new specimen should be ascertained by trial on animals before giving it to man.

Any salt of the alkaloid, curarine, will, however, be more exact in its effects.

Rx Curarinae sulphat., gr. j ; aquae, oz ss. M. Sig. : Four (4) minims contain 1/60 of a grain.

Nicotiana

Nicotine. Rx Nicotianae hydrobromat., mxj ; aquae, 3 iv. M. Sig. : Four (4) minims contain 1/15 of a grain.

Lobelina

Lobeline. Rx Lobelinae hydrobromat., gr. j ; aquae, 3 ij. M. Sig. : Four minims contain 1/15 grain.

Acidum Hydrocyanicum Dilutum

Rx Acid, hydrocyanic. dil., q. s. Sig.: Four minims is the maximum single dose.

Eseria

Eserine. The extract of Calabar-bean dissolved in sufficient water, and filtered, is used hypodermatically, sometimes; but the alkaloid eserine is to be preferred.

Rx Eserinae sulph. vel salicylat., gr. j; aquae, 3iv. M. Sig.: Four (4) minims contain 1/15 of a grain.

Pilocarpina

Pilocarpine. Rx Pilocarpinae hydrochlorat., gr. xvj ; aquae, oz j. M. Sig. : Five (5) minims contain (1/6) one sixth of a grain.

Amyli Nitritum

Nitrite of Amyl. From three (3) to five (5) minims of amyl nitrite can be injected subcutaneously at a time. The repetition of the dose will depend on the effect, but the injection may be practiced every half hour for a time.

Chloroformum Purificatum. Purified Chloroform

Purified Chloroform. From five (5) to fifteen (15) minims can be used at one injection. This agent is employed by the "deep method "—i. e., the chloroform is thrown by the syringe deeply and in the neigh- borhood of the nerve-trunk, the seat of pain.

The official spiritus chloroformi has also been used successfully in the same group of cases.

Alcohol and Ether are also injected subcutaneously alcohol in the diluted form, as whisky or brandy, and pure ether.

Chloral Hydrate

Rx Chloral, hydrat., oz ss. ; aquae, oz j. M. Sig. : Thirty (30) minims contain fifteen (15) grains of chloral.

Sometimes it is advantageous to give chloral and morphine together.

Caffeina

Caffeine. Rx Caffeinae, gr. xxiv; glycerinae, aquae, γγ oz ss. M. Sig. : Twenty minims contain one grain.

Apomorphina

Apomorphine. Rx Apomorphinae, gr. j. Ft. pulv. no. xvj. Sig. : One or more may be dissolved in sufficient water as required.

Apomorphine undergoes a change in the presence of moisture, especially when kept in solution for some time ; hence the solution for hypodermatic injection should be prepared when required. The dose ranges from 1/15 of a grain to 1/6 of a grain.

Ergota. Ergot

Ergot. Rx Ext. ergotae, 3j; aquae, ozj. M. Sig.: Twenty minims contain two (2) grains.

Quinina Disulphat

Quinine. "Rx Quininae disulphat., gr. 1 (50) ; acid, sulphuric. dil., τη, c (100); aquae font., oz j ; acid, carbolic, liq., τη, ν (5). Solve.

"Place the quinine and water in a porcelain dish over a spirit-lamp; heat to the boiling-point, and add the sulphuric acid, stirring with a wooden spatula. Filter at once into a bottle, and add the carbolic acid. This gives six grains to the drachm." [Lente's formula.]

Quinina Bimuriatica carbamidata, a combination of quinine and urea, is freely soluble—in equal parts of water, in fact—and therefore a most useful preparation for hypodermatic use.

Rx Quininae hydrobromat., gr. xlviij ; aquae destil., 3 iv. M. Dissolve, and by heat if necessary. Sig. : Twenty (20) minims contain 4 grains.

The new antipyretics, antipyrine, acetanilid, exalgine, and some others, having been found to possess analgesic power, are now used hypodermatically for the relief of certain kinds of spasmodic and painful diseases.

Acidum Carbolicum (Carbolic Acid)

Carbolic Acid. Rx Acid, carbolic, purif., gr. χ ; aquae, oz j. M. Sig. : Eight minims contain 1/6 of a grain.

The quantity administered will range from one sixth of a grain to two or three grains.

Hydrargyrum

Mercury. The solutions of mercury now chiefly used are those of the corrosive chloride, the albuminate, and the formamide, as prepared by Liebreich.

Rx Hydrarg. chlor, cor., gr. j ; aquae, oz j. M. Sig. : Ten (10) minims contain 1/48 of a grain.

Various albuminous solutions of mercury have been proposed : the chlorides of mercury, ammonium, and sodium, mixed with albumen.

Arsenicum

Arsenic. The preparations of arsenic used hypodermatically are the official solutions and the cacodylates, chiefly cacodylate of sodium, of which one grain is given in sterilized solution.

Aquapuncture Method

By aquapuncture is meant the injection of pure water beneath the skin. A special instrument has been invented to effect this ; but ordinarily a hypodermatic syringe will suffice for this purpose. From a half-drachm to a drachm is thrown under the skin over the organ or part on which it is intended to act.

Irritant Injections

Injections intended to excite local inflammation are also employed in various morbid states. The materials so used, and the conditions requiring them, will be set forth hereafter.