doses are given for a long period, a train of symptoms is produced to which the name, bromism, is applied. These are mental weakness, great drowsiness, failure of memory, anæmia, malnutrition, and depression of spirits, with often impaired sensibility of the mucous and cutaneous surfaces, diminution of the sexual functions, and an eruption on the skin (generally on the face and back), usually of acne, which rarely suppurates, occasionally of eczema, and, very rarely, rupial ulcers may be seen. Elimination: potassium bromide is eliminated chiefly by the kidneys; but, also, by the mucous membranes of the fauces, intestinal canal, and bronchi, by the skin, and by the salivary glands. Traces may be found in the urine ten minutes after its administration, but elimination is slow. No case of acute poisoning by potassium bromide has been reported.

Antagonists and Incompatibles.-Acids, acidulous and metallic salts are incompatible with potassium bromide. It is antagonized in its physiological action by alcohol, ether, coffee, cold, digitalis, strychnine, belladonna, ergot, and other remedies which stimulate the vaso-motor nerves and induce arterial congestion.

It is aided in its action on the brain by cannabis indica, chloral, opium, and similar remedies; the depressing effects on the circulation are enhanced by aconite, veratrum viride, gelsemium, etc.

Medicinal Uses.-From its action on the nervous system, potassium bromide is much used to quiet cerebral excitement and for its sedative effect on the reflex centres of the cord. As a narcotic (by causing anæmia of the brain), it is much used in wakefulness due to cerebral hyperæmia, or even when not more than the normal amount of blood is sent to the brain; in wakefulness and wandering during convalescence from acute diseases; and in sleeplessness due to worry, grief, dyspepsia, and overwork; also in cases of night-horror in children, where they awake suddenly, and scream with fright, often for a considerable time, small doses of this salt and a light supper will frequently effect a cure; adults subject to nightmare will often find relief in the temporary use of potassium bromide; to allay restlessness, remove delusions, calm delirium, and produce sleep

in the early stages of delirium tremens, it is given in doses of gr. xx to xxx every two hours until sleep is produced. It is more efficient in the early stages, and can be relied on with more certainty in the first than in subsequent attacks. Potassium bromide is often combined with other narcotics, as opium, chloral, etc., to aid their action, and even to modify their disagreeable effects. It will generally prove beneficial in women suffering from nervousness; great despondency, amounting to a feeling of approaching madness; irritability; want of interest in their surroundings; sleeplessness and harassing dreams, caused by overwork, want of change, grief, or worry. If the medicine does not succeed alone, it will when combined with a change of scene. In some cases of hysteria, potassium bromide is a valuable remedy. In all forms of convulsions (epilepsy, chorea, convulsions of Bright's disease, convulsions of children, etc.) it will prove beneficial, by diminishing the reflex function of the cord. In epilepsy the bromides are preeminently of service, lessening the frequency of the attacks, if not absolutely preventing their recurrence. It is stated by Trousseau and by Bartholow that it is less efficient in attacks of petit mal than in those of severer form; but Dr. A. Hughes Bennett has recently published a number of cases of the lighter variety, in the majority of which the bromides proved successful. It should be given in sufficient doses to prevent reflex retching or nausea, when the fauces are tickled (Voisin), and must be continued for years, with an occasional intermission of a week or two. Potassium bromide has been successfully used in the treatment of strychnine-poisoning; it should be given in doses of 3ij, frequently repeated, as the case may require. It has also been successfully used in tetanus. It has been recommended during dentition, to allay irritability and restlessness and prevent convulsions. In the reflex forms of vomiting, as the vomiting of pregnancy and of sea-sickness, and in migraine or sick headache (especially in the congestive forms), it is sometimes beneficial. In the colic of infants, unaccompanied by diarrhoea, it is an excellent remedy, relieving pain and spasm, and producing sleep. It is used, too, to obtund the sensibility of the fauces, before the exhibition of the laryngoscope.

From its sedative influence on the organs of generation, it is used with success in nymphomania, spermatorrhoea and masturbation. It decreases the flow of blood in menorrhagia. The flushes of heat, followed by sweating and prostration, occurring at the menopause, are generally cured by the use of potassium bromide.

Administration.-Dose, gr. v-3j or more. In epilepsy it is given in doses of gr. xx-xxx, thrice daily, and continued for a long period, with occasional intervals of a week or two. If bromism occurs, stop the remedy for the time, and give tonics. The bromide rashes are easily cured by withdrawing the medicine, and giving liquor potassii arsenitis internally in small doses, and the local use of an ointment containing iodide of sulphur. Potassium bromide should be administered in solution, and preferably between meals.

AMMONII BROMIDUM-AMMONIUM BROMIDE.

Ammonium bromide (NH,Br) is prepared by mixing bromine with iron wire in distilled water, agitating the mixture until the liquid assumes a greenish colour, and then agitating water of ammonia with the mixture. By evaporation, a white, granular salt is obtained, which, on exposure to the air, gradually becomes yellowish (in consequence of the liberation of hydrobromic acid), has a saline, pungent taste, is very soluble in water, and moderately so in alcohol.

Physiological Effects.-The action of ammonium bromide resembles, in many respects, that of the potassium salt. When applied locally to the motor nerves, spinal centres, heart, or voluntary muscles, it does not destroy their functions, and has less influence, when administered internally, on the circulation, respiration, and temperature.

Medicinal Uses.-It has been used for the same conditions in which potassium bromide is given. Echeverrhia prefers the ammonium bromide in epileptic maniacal excitement, but states that it will fail unless combined with chloral, cannabis indica, or other narcotic, or, better still, with ergot. The combined use of ammonium and potassium bromide has been recommended by Brown-Séquard. Da Costa highly recommends its use in

acute rheumatism. It has also been used with advantage in

pertussis.

Administration. It is given in doses of gr. v-xxx, thrice daily, and is best administered in some bitter infusion.

SODII BROMIDUM (Sodium Bromide) (NaBr) may be prepared in a similar manner to potassium bromide.

In its physiological effects it resembles potassium bromide, but is much feebler.

It is used in the same diseases and in the same doses as is the potassium salt.

LITHII BROMIDUM (Lithium Bromide) (LiBr) has been recommended as the most efficacious of the bromides. S. Weir Mitchell has found it efficient in gr. x-xx doses, in some cases of epilepsy, after potassium bromide had failed. It has been used in gout, but not with much success. It contains a larger per cent. of bromine than do the other salts, and is very soluble.

CALCII BROMIDUM (Calcium Bromide) (CaBr2) has been employed for the same purposes and in the same doses as potassium bromide.

ZINCI BROMIDUM (Zinc Bromide) (ZnBr2) has been employed in the treatment of epilepsy, but its use is not general. Dose, gr. j-xx.

ACIDUM HYDROBROMICUM DILUTUM (Diluted Hydrobromic Acid) is a clear, colourless liquid, without odour, but having a strongly acid taste, which consists of 10 per cent. of absolute Hydrobromic acid (HBr), and 90 per cent. of water. It has a sp. gr. of 1.077.

Effects and Uses.-This acid does not differ materially in its action from potassium bromide, and has been used as a substitute for it in epilepsy, alcoholism, congestive headache, vertigo, chorea, insomnia, hysteria, post-hemiplegic disturbances, etc. It has been recommended to combine it with quinine as a preventive of cinchonism. Its value does not seem to be very firmly established. Dose of the diluted acid, f3ss-ij.

TABACUM-TOBACCO.

Nicotiana Tabacum, or Virginia Tobacco (Nat. Ord. Solanaceæ), is a native of the warm countries of America. It is an

annual plant, growing to the height of from three to six feet, with large oblong, pointed, hairy, pale-green leaves, and lightgreenish, funnel-shaped flowers. The DRIED LEAVES are the portion used. They have a yellowish-brown colour, a strong, peculiar, narcotic odour, and a bitter, nauseous taste. The darker-coloured leaves are the strongest.

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The virtues of tobacco are imparted to alcohol and water, and depend on the presence of an alkaloid called nicotine (C10H1N2), which is found in all parts of the plant. It is a colourless, oily, volatilizable, alkaline liquid, highly soluble in water, alcohol, ether, chloroform, the fixed oils, and oil of turpentine, of a feeble odour when cold, but irritant when heated, of an acrid, burning taste, and is a most energetic poison, ranking after prussic acid. From the dried leaves are also obtained a concrete volatile oil, termed nicotianin, which is probably the odorous principle of the plant, and an empyreumatic oil, which gives the peculiar smell to old tobacco pipes. Both of these principles are poisonous.

Physiological Effects.-Local action: applied to the skin. tobacco is readily absorbed. On persons unaccustomed to its use, tobacco, in small doses, produces nausea, depression, and a feeling of wretchedness. Nervous system: tobacco expends its action on the spinal cord, and not upon the brain, and nicotine, in full doses, acts as a tetanizing agent on man. Nicotine contracts the pupil either locally or internally. The conductivity of the motor nerves is more or less abolished, and lastly that of the spinal cord, while the voluntary muscles remain unaffected. These remarks apply to lethal doses of the drug. Circulation: the blood of a person under the influence of tobacco has been found to present a crenated appearance of the red globules. Tobacco is not a cardiac poison, since the application of nicotine to the cut-out heart will not stop its beats; nevertheless it acts to slow the cardiac action and temporarily reduce blood pressure. It causes death by paralyzing the muscles of respiration. Intestines: tobacco has a relaxing influence upon this tract, and the injection of nicotine induces intestinal peristalsis. Nicotine is probably eliminated by the kidneys. In larger doses, it induces vomiting and purging, a sensation of sinking at the pit