and evaporating to dryness. It is white, granular, inodorous, of a saline, slightly bitterish but not unpleasant taste, deliquescent, and wholly soluble in water (K,CH,O,.H2O). It is an excellent refrigerant diaphoretic, much employed in febrile affections. Dose, gr. xx-xxv; 3vj are usually dissolved in water Oss, and f3ss of the solution is administered every hour or two. The salts of the alkalies with vegetable acids, as citrates, tartrates and acetates, during their passage through the body are converted into carbonates.

Liquor Potassi Citratis (Solution of Potassium Citrate) may be made by dissolving separately citric acid 6 parts and potassium bicarbonate 8 parts in water enough to make the combined solutions weigh 100 parts; dose, f3ss.

Mistura Potassi Citratis (Mixture of Potassium Citrate, or Neutral Mixture) is made by saturating fresh lemon-juice with potassium bicarbonate; or, when the lemon-juice cannot be had, a solution of citric acid, flavoured with oil of lemon, may be used as a substitute. This preparation contains some free carbonic acid, which renders it more grateful to an irritable stomach than the ordinary solution of the citrate. Under the name of effervescing draught the potassium citrate is often prepared extemporaneously (fresh lemon-juice f3ss with an equal measure of water, added to a solution of potassium carbonate 3ij in water fživ), and is given in the state of effervescence; it is an excellent remedy for irritable stomach, with fever.

LIQUOR AMMONII ACETATIS-SOLUTION OF AMMONIUM ACETATE.

This solution, termed also Spiritus Mindereri, or Spirit of Mindererus, is made by saturating diluted acetic acid with ammonium carbonate, and is a solution of ammonium acetate (NH,C,H,O2). When pure it is a colourless liquid, with a saline taste; it should always be made freshly when dispensed. The physiological effects of the ammonium salts have already been considered (vide p. 180). In small doses it is refrigerant; in larger doses, diaphoretic, diuretic, and perhaps resolvent. It is employed in febrile and inflammatory affections, sometimes in conjunction with nitre or one of the sedatives, sometimes

with camphor and opium. Given in full doses, frequently repeated, it is one of the best means of removing the effects of drunkenness. Dose, f3ss-j every two, three or four hours, in sweetened water.

SPIRITUS ÆTHERIS NITROSI-SPIRIT OF NITROUS ETHER.

This preparation, commonly known as Sweet Spirit of Nitre, is a solution of ethyl nitrite (C,H,NO2) in alcohol. Spirit of nitrous ether is a volatile, inflammable liquid, of a pale-yellow colour, inclining slightly to green, has a fragrant, ethereal odour, free from pungency, and a sharp, burning taste, and mixes with water and alcohol in all proportions; sp. gr. o.823 to 0.825. It contains five per cent. of nitrous ether. It should not be long kept, as it becomes strongly acid by age.

Effects and Uses.-Sweet spirit of nitre is antispasmodic, refrigerant, diaphoretic, and diuretic. As a diaphoretic, small doses should be given, largely diluted and frequently repeated. It is much used in febrile affections, and, from its diuretic properties, is often combined with other diuretics in the treatment of dropsies. From its pleasant taste and smell it is very acceptable to children. Dose, f3ss-j, frequently repeated. The inhalation of sweet spirit of nitre has produced dangerous and even fatal effects: pallor of the face, livid discoloration of the lips and fingers, weakness of the pulse, muscular prostration, præcordial oppression, and headache are the symptoms described. A case is recorded in which death was attributed to the inhalation of the ether from a broken bottle in a sleeping apartment. The same symptoms may be produced by excessive doses.

ACIDA VEGETABILIA-VEGETABLE ACIDS.

The vegetable acids are refrigerant, and, when properly diluted, form useful drinks in fevers, etc. Those chiefly employed are acidum aceticum (acetic acid), acidum citricum (citric acid), and acidum tartaricum (tartaric acid).

Effects and Uses.-Applied to a raw surface or (if sufficiently concentrated) to the mucous membranes, they act as irritants. Acetic acid is the most powerful, and will, when applied to the

skin, cause blanching from contraction of the capillaries. Citric acid is the least irritant. After large doses the cardiac beat is slowed and weakened, but this is possibly due to the resulting gastro-enteritis (Bartholow). The alkalinity of the blood is diminished. The general law regarding the action of acids on secretion holds good in the case of the vegetable acids, viz.: that when applied to the orifices of glands secreting an acid fluid they diminish, while when applied to glands secreting an alkaline fluid they increase their secreting power. Thus they increase the saliva and the intestinal secretion. The ingestion of the vegetable acids increases the acidity of the urine. They also increase the excretion of both the water and the solids of the urine, particularly free uric acid (and may thus lead to calculus). Their continued use causes abdominal pain, flatulence, and diarrhoea. In large doses they may produce gastroenteritis. They are mostly converted into carbonic acid in the system, and are eliminated by the kidneys and intestinal mucous membrane.

ACETIC ACID (HC,H,O2) is employed internally only in the form of diluted acetic acid (strong acid 17 parts to distilled water 83 parts). Externally, strong acetic acid (sp. gr. 1.048, and containing 36 per cent. of monohydrated acid) or glacial acetic acid (nearly absolute acetic acid-sp. gr. 1.058) is employed as an escharotic to remove warts, in the cure of lupus, etc. Acetic acid is less used internally as a refrigerant than citric acid, from its liability to produce colic and diarrhoea, except in typhus, scarlet and other malignant fevers, owing to its supposed possession of antiseptic virtues. Vinegar and water is one of the best injections for the cure of vaginal gonorrhoea in the female. Spongings with vinegar and water are useful to relieve the heat of the skin in fevers, and the vapour is grateful to the sick. Concentrated acetic acid is a corrosive poison, for which the alkalies and their carbonates, soap, etc., are the antidotes. CITRIC ACID may be agreeably administered in the diluted juice of lemons, limes, sour oranges, and tamarinds. When these cannot be obtained, a solution of citric acid (gr. xx to water Oj) may be substituted. Citric acid is manufactured from lemon or lime juice, by saturating it with calcium carbon

ate and afterwards decomposing the calcium citrate, which is formed, by the addition of sulphuric acid. It occurs in colourless crystals (H ̧CH ̧О,H2O), having the form of rhomboidal prisms with dihedral summits, freely soluble in water, and soluble in alcohol; 3ixss, added to distilled water Oj, form a solution of the average strength of lemon juice. In the dose of f3j every hour or two, lemon juice, limonis succus (the juice of the fruit of Citrus Limonum), has been employed with success in acute rheumatism and gout, and, though an uncertain remedy, is occasionally of undoubted efficacy. Of late years, however, it has given place to more reliable modes of treatment. Properly diluted and mixed with sugar, it forms the delightful refrigerant known as lemonade. Lemon-juice (or, still better, lime-juice) is the most efficient known remedy for scurvy. It has also proved of advantage in jaundice and torpor of the liver. Syrup of citric acid consists of citric acid (8 parts) and water (8 parts) with oil of lemon (4 parts) and syrup (980 parts). Lemon syrup, which is pleasanter, is made by heating lemon-juice (40 parts) to the boiling point; adding lemon peel (2 parts); and letting it stand until cool; then filter and add enough water to make the filtrate weigh 40 parts; dissolve sugar (60 parts) in the filtrate and strain. Spirit of Lemon (sometimes called essence of lemon) is made by dissolving oil of lemon 6 parts (obtained from the rind of the fruit), in alcohol 90 parts, and adding freshlygrated lemon-peel 4 parts; dose, f3j-ij. TARTARIC ACID is the acid of grapes, and is extracted from tartar or crude cream of tartar. It is a white crystallized solid, in the form of irregular six-sided prisms (H,C,H,O), and is found in the shops as a fine white powder. It is soluble in water and alcohol. Being cheaper than citric acid, it may be used as a substitute for that acid. It is employed in making Seidlitz powders. Tartaric acids yields a precipitate (cream of tartar) with a solution of carbonate or other neutral salt of potassium, while citric acid yields none.

ORDER VIII.-SPINANTS.

Under the term Spinants, or Spastics, are comprised medicines which are employed to excite muscular contraction, or

whose ultimate effect is the production of motor paralysis, and may, accordingly, be divided into excito-motors and depressomotors. Of the first class, the most important articles are vegetable substances containing the alkaloids strychnine and brucine, which are employed therapeutically in torpid or paralytic conditions of the muscular system; ergot, which is used to excite muscular contraction of the uterus; and digitalis, which is given for its tonic effect on the heart. The latter class contains such remedies as conium, physostigma, woorara,

etc.

EXCITO-MOTORS.

NUX VOMICA.

Strychnos Nux vomica, or Poison-Nut (Nat. Ord. Loganiacaca), is a middling-sized tree of the coast of Coromandel and other parts of India, which bears a round, smooth berry, the size of a pretty large apple, of a rich orange colour, and containing numerous seed imbedded in a juicy pulp. The SEED are the officinal portion; but the bark also is poisonous, and is known as false angustura bark, from its having been confounded with angustura bark. The seed are round, peltate, less than an inch in diameter, nearly flat, or convex on one side and concave on the other, and surrounded by a narrow annular stria. They have two coats: a simple fibrous outer coat, covered with short, silky hairs, of a gray or yellowish colour, and a very thin inner coat which envelops the nucleus or kernel. This is hard, horny, of a whitish or yellowish colour, and of very difficult pulverization. The seed have no odour, but an intensely bitter taste, which is stronger in the kernel than in the investing membrane. They impart their virtues to water, but more readily to diluted alcohol, and contain two active alkaloid principles, strychnine (which is officinal) and brucine, both of which exist in combination with an acid called igasuric; another alkaloid, termed igasurine, much more soluble in water than the two first named, has been lately extracted from nux vomica.

STRYCHNINA (Strychnine) (CH2N2O2) is obtained by the following process: Nux vomica is digested and boiled in water acidulated with hydrochloric acid, and the resulting