Properties and Uses. - Antiseptic; it is absorbed rapidly, a value due to its partial change into and liberation as formaldehyde in the urine. The urine usually is rendered acid, but should it remain alkaline no decomposition takes place, nor is any antiseptic action secured; solvent for uric acid; similar to piperazine; pyelitis, cystitis, phosphaturia, gonorrhoea, typhoid fever, renders urine clear and acid when loaded with pus, urates and phosphates.

Paraldehydum. Paraldehyde. - (Syn., Paraldehyd.; Fr. Paraldehyde, Elaldehyde; Ger. Paraldehyd.) A polymer of acetaldehyde, C2H4O.

Manufacture: Paraldehyde (Gr.

resembling, +) is obtained usually by passing hydrochloric acid gas into aldehyde, or by adding to ordinary (ethyl) aldehyde a small quantity of either SO2, HC1, ZnCl2, or sodium acetate; the temperature of the mixture rises, and almost a complete conversion into paraldehyde takes place. It is a colorless, transparent liquid, strong, characteristic, but not unpleasant or pungent odor, at first a burning then a cooling sensation in the mouth; soluble in water (8), boiling water (17), miscible with alcohol, chloroform, ether, volatile oils, neutral or slightly acid, sp. gr. 0.990, boils at 123° C. (253° F.), congeals at 6° C. (43° F.); when heated with a little sulphuric acid is converted into acetaldehyde, recognized by its odor. Impurities: Amyl alcohol, sulphuric acid, hydrochloric acid, free acid acetaldehyde, substances from fusel oil. Should be kept cool, dark, in well-closed containers. Dose, exv-60 (1-4 Ml. (Cc.)), largely diluted with syrup and flavored with tincture of orange peel or some aromatic, the taste being disagreeable.

Properties. - Soporific, hypnotic, antiseptic; no influence over pain. Excessive doses weaken heart-action. Kills by paralysis of the respiratory centre, moderate doses cause 5-7 hours of refreshing, dreamless sleep, without unpleasant after-effects. May create paraldehyde-habit, emaciation, etc.

Uses. - Same indications as hydrated chloral - insomnia from mental strain, insanity, mania, melancholia, delirium tremens, cardiac affections, allays itching in jaundice, vomiting in nauseating headache, pregnancy, and irritable ovary, excellent in strychnine-poisoning, morphine-habit, often produces erythematous rash.

Chloralum Hydratum. Hydrated Chloral. - (Syn., Chloral. Hydrat., Chloral, Chloral Hydrate, Aldehydum Trichloratum, Hydrous Chloral, Trichloraldehyde Hydrate; Br. Chloral Hydras; Fr. Hydrate de Chloral; Ger. Chloralum hydratum, Chloralhydrat.) A compound of trichloraldehyde or chloral with the elements of 1 molecule of water.

Manufacture: Chloral (chlor(ine) + al(cohol)) is acetic aldehyde, C2H4O, in which 3 hydrogen atoms have been replaced by 3 chlorine atoms, and is made, as the name would suggest, by passing dry chlorine gas into anhydrous alcohol until saturated, which requires from a few hours to many weeks, according to amount of alcohol operated upon; when hydrochloric acid gas ceases to distil the temperature is increased gradually to 70° C. (158° F.), and the saturated liquid, which congeals on cooling, is shaken with sulphuric acid to decompose chloral alcoholate, remove alcohol and other impurities; the colorless oily layer that separates is removed and rectified direct over lime and calcium carbonate; this rectified distillate (anhydrous chloral) is mixed with water (82 parts chloral + 10 water), mixture poured upon plates under bell-glass, and allowed to crystallize - hydrated chloral - C2H6O + 2C1 = C2H4O + 2HC1; C2H4O + 6C1 = C2HC13O + 3HC1. It is in rhomboidal, colorless, transparent crystals, aromatic, penetrating, slightly acrid odor, bitterish, caustic taste, soluble in water (.25), alcohol (1.3), chloroform (2), ether (1.5), olive oil, oil of turpentine; liquefies when treated with an equal quantity of camphor, menthol, phenol, or thymol; decomposed by caustic alkalies, alkaline earths, ammonia, chloroform - a formate of the base being produced; contains 99.5 p. c. of hydrated chloral. Tests: 1. Warm with a few drops of aniline and sodium hydroxide T. S. - intensely disagreeable odor of phenyl-isocyanide. 2. Incinerate - ash .05 p. c.; does not readily attract moisture. Impurities: Hydrochloric acid, chlorides, chloral alcoholate, ethyl carbonate, organic substances. Should be kept cool, dark, in tightly-stoppered bottles. Dose, gr. 5-20 (.3-1.3 Gm.), not safe to exceed this owing to possible cumulative tendency, etc.

Preparations. - (Unoff.): Mistura Chloralis et Potassii Bromidi Composita, 20 Gm., + potassium bromide 20, extract of cannabis .2, extract of hyoscyamus .2, pumice 2, water q. s. 100, dose, 3ss-2 (2-8 Ml. (Cc.)). Syrupus Chloral (Br.), 20 p. c, dose, 3ss-2 (2-8 Ml. (Cc.)).

Properties. - Externally - antiseptic, vesicant, irritant, anodyne. Internally - soporific, hypnotic, gastric irritant, general depressant (vasomotor centre, also heart becomes slow, feeble, irregular, stopping in diastole), produces sleep quickly, is certain, and has no unpleasant after-effects, circulates in the blood unchanged, may be decomposed finally if urine is alkaline.

Uses. - Externally - mixed with camphor, menthol, etc., anodyne in neuralgia, caries of teeth, for toothache, foul sores, ulcers, fetor of feet, chapped nipples, erectile tumor, gonorrhoea, diphtheria, night-sweats. Internally - nervous insomnia from overwork, worry, etc., acute fevers, acute congestion of brain, cerebral inflammation, mania, delirium tremens, tetanus, hysteria, chorea, epilepsy, local spasms, asthma, strangulated hernia, spasm of the glottis, spasmodic croup, hiccough, incontinence of urine, insanity, to relieve pain, nervous headache, angina pectoris, convulsions, whooping-cough, dysentery, typhoid fever, strychnine, hyoscine, and calabar bean poisoning.