Medicines should be given in such a manner that the effect of the first dose shall not have ceased when the next dose is given, therefore the intervals between the doses should be regulated accordingly.

688. Doses of Medicine for Different Ages.

It must be plain to every one that children do not require such powerful medicine as adults or old people, and therefore it is desirable to have some fixed method of determining or regulating the administration of doses of medicine. Now let it be supposed that the dose for a full-grown person is one drachm, then the following proportions will be suitable for the various ages given; keeping in view other circ.u.mstances, such as s.e.x, temperament, habits, climate, state of _general health_, and idiosyncrasy.

Age. Proportion. Proportionate Dose.

7 weeks one-fifteenth or grains 4 7 months one-twelfth or grains 5 Under 2 years one-eighth or grains 7-1/2 " 3 " one-sixth or grains 10 " 4 " one-fourth or grains 15 " 7 " one-third or scruple 1 " 14 " one-half or drachm 1/2 " 20 " two-fifths or scruples 2 Above21 " the full dose or drachm 1 " 65 " The inverse gradation

689. Drugs, with their Properties and Doses.

The various drugs have been arranged according to their properties, and the doses of each have been given. Many, however, have been necessarily omitted from each cla.s.s, because they cannot be employed except by a medical man. The _doses_ are meant for adults.

690. Cla.s.ses of Drugs.

Medicines have been divided into four grand cla.s.ses

1. General stimulants; 2. Local stimulants; 3. Chemical remedies; 4. Mechanical remedies.

691. General Stimulants.

General stimulants are subdivided into two cla.s.ses, diffusible and permanent stimulants: the first comprising narcotics and antispasmodics, and the second tonics and astringents.

692. Narcotics.

Narcotics are medicines which stupefy and diminish the activity of the nervous system. Given in small doses, they generally act as stimulants, but an increased dose produces a sedative effect. Under this head are included alcohol, camphor, ether, the hop, and opium.

693. Alcohol.

Alcohol, or rectified spirit, is a very powerful stimulant, and is never used as a remedy without being diluted to the degree called proof spirit; and even then it is seldom used internally. It is _used externally_ in restraining bleeding, when there is not any vessel of importance wounded. It is also used as a lotion to burns, and is applied by dipping a piece of lint into the spirit, and laying it over the part. Freely diluted (one part to eighteen) with water, it forms a useful eye-wash in the last stage of ophthalmia.

_Used internally_, it acts as a very useful stimulant when diluted and taken moderately, increasing the general excitement, and giving energy to the muscular fibres; hence it becomes very useful in certain cases of debility, especially in habits disposed to create acidity; and in the low stage of typhus fevers.

_Dose_.--It is impossible to fix anything like a dose for this remedy, as much will depend upon the individual; but diluted with water and sweetened with sugar, from half an ounce to two ounces may be given three or four times a day. In cases of extreme debility, however, much will depend upon the disease.

_Caution_.--Remember that alcohol is an irritant _poison_, and that daily indulgence in its use originates dyspepsia, or indigestion, and many other serious complaints. Of all kinds of spirits the best as a tonic and stomachic is _brandy_.

[TO-MORROW, SINKS INTO THE SILENT TOMB.]

694. Camphor.

Camphor is not a very steady stimulant, as its effect is transitory; but in large doses it acts as a narcotic, abating pain and inducing sleep. In moderate doses it operates as a diaph.o.r.etic, diuretic, antispasmodic, increasing the heat of the body, allaying irritation and spasm.

It is _used externally_ as a liniment when dissolved in oil, alcohol, or acetic acid, being employed to allay rheumatic pains; and it is also useful as an embrocation in sprains, bruises, chilblains, and, when combined with opium, it has been advantageously employed in flatulent colic, and severe diarrhoea, being rubbed over the bowels.

_When reduced to a fine powder_, by the addition of a little spirit of wine and friction, it is very useful as a local stimulant to indolent ulcers, especially when they discharge a foul kind of matter; a pinch is taken between the finger and thumb, and sprinkled into the ulcer, which is then dressed as usual.

_When dissolved in oil of turpentine_, a few drops placed in a hollow tooth and covered with jeweller's wool, or sc.r.a.ped lint, give almost instant relief to toothache. _Used internally_, it is apt to excite nausea, and even vomiting, especially when given in the solid form.

_As a stimulant_ it is of great service in all low fevers, malignant measles, malignant sore throat, and confluent small-pox; and when combined with opium and bark, it is extremely useful in checking the progress of malignant ulcers, and gangrene.

_As a narcotic_ it is very useful, because it allays pain and irritation, without increasing the pulse very much.

_When powdered and sprinkled_ upon the surface of a blister, it prevents the cantharides acting in a peculiar and painful manner upon the bladder.

_Combined with senna_, it increases its purgative properties; and it is also used to correct the nausea produced by squills, and the irritating effects of drastic purgatives and mezereon.

_Dose_, from four grains to half a scruple, repeated at short intervals when used in small doses, and long intervals when employed in large doses.

_Doses of the various preparations_.--Camphor mixture, from half an ounce to three ounces; compound tincture of camphor (_paregoric elixir_), from fifteen minims to two drachms.

_Caution_.--When given in an overdose it acts as a poison, producing vomiting, giddiness, delirium, convulsions, and sometimes death. Opium is the best antidote for camphor, whether in excess or taken as a poison. _Mode of exhibition_.--It may be rubbed up with almond emulsion, or mucilage, or the yolk of eggs, and by this means suspended in water, or combined with chloroform as a mixture, in which form it is a valuable stimulant in cholera and other diseases. (_See_ Mixtures, 556-564).

695. Ether.

Ether is a diffusible stimulant, narcotic and antispasmodic.

696. Sulphuric Ether

Sulphuric Ether is used _externally_ both as a stimulant and a refrigerant. In the former case its evaporation is prevented by covering a rag moistened with it with oiled silk, in order to relieve headache; and in the latter case it is allowed to evaporate, and thus produce coldness: hence it is applied over scalded surfaces by means of rags dipped in it.

_As a local application_, it has been found to afford almost instant relief in earache, when combined with almond oil, and dropped into the ear.

It is used _internally_ as a stimulant and narcotic in low fevers and cases of great exhaustion.

_Dose_, from fifteen minims to half a drachm, repeated at short intervals, as its effects soon pa.s.s off. Give in a little camphor julep, or water.

697. Nitric Ether

Nitric Ether is a refrigerant, diuretic, and antispasmodic, well known as "_sweet spirit of nitre_."

_Used externally_, its evaporation relieves headache, and it is sometimes applied to burns. It is used _internally_ to relieve nausea, flatulence, and thirst in fevers; also as a diuretic.

_Dose_, from ten minims to one drachm. The smaller dose taken in a little warm water or gruel is useful as a sudorific in cases of cold and chill, to induce and promote the proper action of the skin which has been checked. If a larger dose be taken, it acts as a diuretic and not as a sudorific, and so fails to produce the desired effect.