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Pharmaceutical Operations

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PHARMACEUTICAL OPERATIONS.

Under this head we shall comprise the mode of collecting and preserving medi cinal simples; the mechanical instru ments employed, and the changes they introduce ; chemical instruments and ap paratus, their use, application and power, Collection and Preservation of Simples.

Each of the kingdoms of nature fur nishes articles employed in medicine in their natural state, or when prepared by pharmacy ; and in collecting these, our first attention should be to make choice of sound and perfect substances ; to throw off whatever is injured or decayed, and to separate them from all adventitious matters. As a general rule, they must be deli tided from the t fleets of moisture, great heat, cold, and freely exposed to the air. Yet when their activity and virtue depend on volatile principles, instead of being freely exposed to the air, they must be confined, as much as possible, from its contact.

The vegetable kingdom affords us the most numerous articles; these should ra ther be obtained from countries in which they grow naturally, than countries in which they merely grow by transplanta tion ; and those which grow wild, in dry soils, and exposed situations, fully open to the air and the sun, are for the most part to he preferred to plants that are cul tivated, or that grow in moist, low, shady, and confined situations. Annual roots should be collected before they shoot forth their stalks or flowers ; biennial roots in the harvest of their first year, or the springtime of their second ; peren nial roots either in the spring time before the sap has begun to mount, or in har vest after it has returned. Worm-eaten or decayed roots, except in a few cases of resinous plants, are to be rejected ; the rest are to be cleaned immediately with a brush and cold water ; immersing them in the water as short a time as pos sible, and cutting off the radicles and fi bres when not essential. Roots which consist chiefly of fibres, and have but a small sap, may be dried at once ; if juicy and not aromatic, in a heat somewhat be low 100° of Fahrenheit; but if aromatic, by simply exposing them to a current of cold dry air, and frequently turning them in it. If very thick and strong, they

must be split and cut into slice(, and strung upon threads; if covered with a tough bark they may be peeled and dried while fresh. Such as lose their virtues by drying are to be kept buried in dry sand.

It is difficult to lay down general rules for collecting stalks and leaves, some of which acquire, while others lose their ac tivity by age. Aromatics should be col lected after the flower-buds are formed; non-aromatics, if annuals, when in flower, or about to flower; biennials before they shoot; and perennials before they flower, especially the woody-fibred. They should be gathered in dry weather, after the morning dew is off, or before it falls in the evening. Generally speaking, they should be tied in bundles, and hung up in a shady, warm, and airy place, or spread upon the floor, and frequently turned.

If very juicy, they are to be laid upon :4 sieve, and dried by a gentle degree of artificial warmth. Sprouts are to be col lected before the buds open; and stalks to be gathered in autumn. Barks are to be collected when the most active parts of the vegetable are concentrated in them. Spring is preferred for resinous barks, and autumn for the others which are rather gummy than resinous. Young trees afford the best bark for medical pur poses.

The same rules apply to the collection of woods; but they must not be taken from very young tiecs. Among the re sinous woods, the heaviest, which sink in water, are selected. The alburnum is to be rejected.

Flowers are collected in clear dry wea ther, before noon, but after the dew is off; either when they are just about to open, or immediately after they have opened. Of some the petals only are preserved, and the colourless claws are even cut away; of others, whose calyx is 'odorous, the whole flower is kept. Flow ers which are too small to be pulled singly, are dried with part of the stalk: these are called heads or tops.

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