Be careful not to pound too hard in gla.s.s, porcelain, or Wedgwood-ware mortar; they are intended only for substances that pulverize easily, and for the purpose of mixing or incorporating medicines. Never use acids in a marble mortar, and be sure that you do not powder galls or any other astringent substances in any but a bra.s.s mortar.

669. Sifting.

Sifting is frequently required for powdered substances, and this is usually done by employing a fine sieve, or tying the powder up in a piece of muslin, and striking it against the left hand over a piece of paper.

670. Filtering.

Filtering is frequently required for the purpose of obtaining clear fluids, such as infusions, eye-washes, and other medicines; and it is, therefore, highly important to know how to perform this simple operation. First of all take a square piece of white blotting paper, and double it over so as to form an angular cup. Open out this filter paper very carefully, and having placed it in a funnel, moisten it with a little water. Then place the funnel in the neck of the bottle, and pour the liquid gently down the side of the paper, otherwise the fluid is apt to burst the paper.

671. Maceration.

Maceration is another process that is frequently required to be performed in making up medicines, and consists simply in immersing the medicines in _cold water_ or spirits for a certain time.

672. Digestion.

Digestion resembles maceration, except that the process is a.s.sisted by a gentle heat. The ingredients are placed in a flask, such as salad oil is sold in, which should be fitted with a plug of tow or wood, and have a piece of wire twisted round the neck. The flask is held by means of the wire over the flame of a spirit lamp, or else placed in some sand warmed in an old iron saucepan over the fire, care being taken not to place more of the flask below the sand than the portion occupied by the ingredients.

673. Infusion.

Infusion is one of the most frequent operations required in making up medicines, its object being to extract the aromatic and volatile principles of substances, that would be lost by decoction, or digestion; and to extract the soluble from the insoluble parts of bodies. Infusions may be made with cold water, in which case they are weaker, but more pleasant. The general method employed consists in slicing, bruising, or rasping the ingredients first, then placing them in a common jug (which should be as globular as possible), and pouring boiling water over them. Cover the jug with a cloth folded six or eight times, but if there be a lid to the jug so much the better. When the infusion has stood the time directed, hold a piece of _very coa.r.s.e_ linen over the spout, and pour the liquid through it into another jug.

[TO-MORROW, POOR--OR LIFE ITSELF DENIED.]

674. Decoction.

Decoction, or boiling, is employed to extract the mucilaginous or gummy parts of substances, their bitter, astringent, or other qualities, and is nothing more than boiling the ingredients in a saucepan with the lid slightly raised. Be sure never to use an iron saucepan for astringent decoctions, such as oak-bark, galls, &c., as they will turn the saucepan black, and spoil the decoction. The enamelled saucepans are very useful for decoctions, but an excellent plan is to put the ingredients into a jar and boil the jar, thus preparing it by a water bath, as it is technically termed; or by using a common pipkin, which answers still better. No decoction should be allowed to boil for more than ten minutes.

675. Extracts.

Extracts are made by evaporating the liquors obtained by infusion or decoction, but these can be bought much cheaper and better of chemists and druggists, and so can tinctures, confections, cerates and plasters, and syrups: but as every one is not always in the neighbourhood of druggists, we shall give recipes for those most generally useful, and the method of making them.

676. Precautions to be observed in Giving Medicines.

677. s.e.x.

Medicines for females should not be so strong as those for males, therefore it is advisable to reduce the doses about one-third.

678. Temperament.

Persons of a phlegmatic temperament bear stimulants and purgatives better than those of a sanguine temperament, therefore the latter require smaller doses.

679. Habits.

Purgatives never act so well upon persons accustomed to take them as upon those who are not, therefore it is better to change the form of purgative from pill to potion, powder to draught, or aromatic to saline. Purgatives should never be given when there is an irritable state of the bowels.

680. Use of Alcohol.

Stimulants and narcotics never act so quickly upon persons accustomed to use spirits freely as upon those who live abstemiously.

681. Climate.

The action of medicines is modified by climate and seasons. In summer, certain medicines act more powerfully than in winter, and the same person cannot bear the dose in July that he could in December.

682. General Health.

Persons whose general health is good bear stronger doses than the debilitated and those who have suffered for a long time.

683. Idiosyncrasy.

By this is meant a peculiar temperament or disposition not common to people generally. For example, some persons cannot take calomel in the smallest dose without being salivated, or rhubarb without having convulsions; others cannot take squills, opium, senna, &c.; and this peculiarity is called the patient's idiosyncrasy, therefore it is wrong to _insist_ upon their taking these medicines.

684. Forms best suited for Administration.

Fluids act quicker than solids, and powders sooner than pills.

685. Best Method of Preventing the Nauseous Taste of Medicines.

Castor oil may be taken in milk, coffee, or spirit, such as brandy; but the best method of covering the nauseous flavour is to put a tablespoonful of strained orange juice in a winegla.s.s, pour the castor oil into the centre of the juice, and then squeeze a few drops of lemon juice upon the top of the oil. The winegla.s.s should first be dipped, rim downwards, into water, so that the interior may be wetted.

Cod liver oil may be taken, like castor oil, in orange juice.

Peppermint water neutralizes, to a great extent, the nauseous taste of Epsom salts; a strong solution of extract of liquorice, that of aloes; milk, that of cinchona bark; and cloves that of senna.

[TO-DAY, LAYS PLANS FOR MANY YEARS TO COME.]

686. An Excellent Way to Prevent the Taste of Medicines

is to have the medicine in a gla.s.s, as usual, and a tumbler of water by the side of it; take the medicine, and retain it in the mouth, which should be kept closed, and if drinking the water be then commenced, the taste of the medicine is washed away. Even the bitterness of quinine and aloes may be prevented by this means. If the nostrils are firmly compressed by the thumb and finger of the left hand, while taking a nauseous draught, and so retained till the mouth has been washed out with water, the disagreeable taste of the medicine will be almost imperceptible.

687. Giving Medicines to Persons.