Roots and herbs
Collect such as are perfect and sound, and separate from them such as are injured or decayed. Those precautions must be taken which are best fitted for preserving them, and they should, as a general rule, be defended from the effects of moisture, too great heat, or cold, and confined air. Vegetable matters should be collected in the countries where they are indigenous, and those which grow wild in dry soil and high situations, fully exposed to the air and sun, are, in general, to be preferred to those which are cultivated, or which grow in moist, low, shady, or confined places.
Roots which consist principally of fibres, and have but a small top, may be immediately dried, if they are juicy, and not aromatic; this may be done by heat, not 100 degrees of Fahrenheit; but, if aromatic, by simply exposing and turning them frequently in a current of dry air; if they are thick and strong, they should be split or cut into slices, and strung upon thread; if covered with a rough bark, they may be peeled fresh, then dried. Such as lose their virtues by drying, or are directed to be preserved in a fresh state, are to be kept buried in dry sand.
No very general rule can be given for the collection of herbs and leaves– some of them acquiring activity by age, and others, as the mucilaginous leaves, from the same cause, losing the properties for which they are efficient. Aromatics are to be gathered after the flower buds are formed; annuals, not aromatic, when they are about to flower, or when in flower; biennials, before they shoot, and perennials, before they flower, especially if their fibres become woody; they are to be gathered in dry weather, after the dew is off them, or in the evening, before it falls, and are to be freed from decayed, withered, or foreign leaves; they are usually 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 laid upon a sieve, and dried by a gentle degree of artificial warmth, by the stove.
Sprouts are collected before the buds open, and stalks are gathered in autumn.
Barks and woods are collected when the most active part of the vegetable are concentrated in them, which occurs in spring and in autumn; spring is preferred for resinous barks, and autumn for others, which are not resinous, but rather gummy. Barks should be taken from young trees. Among the resinous woods, the heaviest, which sink in water, are selected; the alburnum is to be rejected.
Flowers are collected in dry weather, 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 colorless claws are even cut away; of others, whose calyx is odorous, the whole flower is kept. Flowers which are too small to be pulled singly, are dried with part of the stalk, and are called heads, or tops. Flowers and herbs are to be dried by the gentle heat of a stove, or common fire, in such quantities at a time, that the process may be finished as quickly as possible– for by this means their powers are best preserved, the test of which is the perfect preservation of their natural color; when they lose their color and smell, they are unfit for use.
Fruits and seeds, unless when otherwise directed, are to be gathered when ripe, but before they fell spontaneously. Some pulpy fruits are freed from their core, and seeds are strung on thread, and dried artificially; they are, in general, best preserved in their natural coverings, although some, as the colacynth, are peeled, and others, as the tamarind, preserved fresh. Many of these are apt to spoil, or become rancid; and as they are then no longer fit for medical use, no very large quantity of them should be collected at a time.
When, on account of the color, they can not be exposed to the sun, and the warmth of the atmosphere is insufficient, they should be dried by an artificial warmth, less than 100 degrees of Fahrenheit, and well exposed to a current of air. When perfectly dry and friable, they have little smell, but after being kept some time, they attract moisture from the air, and regain their proper odor.
Fruits and oily seeds, which are apt to become rancid, must be kept in a cool and dry , and by no means in a warm or moist place. Vegetables collected in a rainy and moist season are, in general, more watery, and apt to spoil; in a dry season, they contain more oily and resinous particles, and keep much better.