Leaves and herbs are, as a rule, collected when the plant is in full flower. Many tests have shown that at that stage the desirable principles, whether alkaloids or volatile oils, are most abundant. In the case of biennials, the leaves of the two years are often not of equal value ; e.g., foxglove leaves are taken the second year when the plant is in flower.
Flowers are sometimes collected in the bud stage, as in insect flowers, or soon after the flower has well opened, as in camomile. Calendula flowers are harvested at this stage by pulling off the bright colored ray flowers, which alone make up the drug. Fruits are frequently collected a little before they are thoroughly ripe in order to secure a bright apii,arance in the crude article, as in conium, cori ander, anise, fennel and American wormseed. Others are allowed to ripen thoroughly, as red peppers and chiiiies. Some fruits are collected and allowed to dry before the seeds obtained from them are separated, as opium poppy, stranioniuni and castor beans.
Methods of preparation.
Usually the products of medicinal, condimental and aromatic plants are not used when fresh, but have to be got into a condition permitting storage or shipment so that they may be used at a distance or at some later time. The homeopathic school of medicine makes it a strong point to use plant drugs in a fresh condition or preserved by immer sion in alcohol. In general, the preservation of these products is brought about by simple drying. When dry many of them retain their most impor tant properties for use. The live roots are care fully cleaned by washing, and if not too large for easy drying are merely spread out in some airy place. If too large, they are cut up, frequently into characteri tic forms. Leaf products are dried in the shale with natural heat or over a gentle artificial heat, about 125° Fahr.. In order to secure a bright green color, pains must be taken to keep the leaves from taking up moisture at any stage. When dry they should be stored out of strong light. Barks are usually "rossed" before drying, i. e., the dead outer corky parts are scraped off. In the case of some drugs, as cascara bark, a more or less prolonged period of storage is neces sary before use. Flowers and fruits are best when dried as promptly as possible without raising the temperature to a point likely to drive off more of the volatile substances than is necessary. Nearly
all drug and condiment products leave the hands of the growers in the form of the crude, dry prod ucts, which are worked up by the manufacturers into the proper forms for use.
condimental and aromatic plant impor tation.
The sources of our crude drugs and condiments are very widely separated, depending in large part on climatic conditions. Common drug plants belonging to the temperate zone, such as digitalis, burdock and caraway, are in very large part pro duced in northern and central Europe, frequently in more or less localized regions. Caraway comes chiefly from Holland, in small quantities from Norway, east Prussia and southern Germany. Fennel is cultivated in Saxony, Galicia, Macedonia and Italy. Digitalis leaves and belladonna reach the market from northern Germany, Austria, Belgium, Holland and England. Peppermint oil is produced chiefly in Japan and the United States. Other plants demanding tropical conditions are obtained from regions in which their culture has been undertaken. Cinchona bark, from which quinine is obtained, came formerly from the slopes of the Andes. Cultivation of this plant in India, Java, and other parts of the Orient has succeeded in so far as to cause the practical disappearance of the wild barks of South America from the market. Ipecacuanha, likewise a native of northern South America, is apparently repeating this history. Black and white pepper are chiefly produced in southeastern Asia, coming on the market through Singapore and Penang. Cloves are in large part supplied by Zanzibar, where the crop constitutes one of the royal monopolies. Some products are derived from still more localized regions, as buchu leaves from the vicinity of Cape Town, South Africa, and aloes from South Africa, the island of Socotra in the Red sea, and the Barbadoes islands. Some are cultivated, as may be seen in numerous cases cited above, and some are wild products. Camphor until recently has been derived from an essentially wild tree growing in Japan, China and Formosa. The great depletion of the natural for ests has led the Japanese government to make extensive plantings. Several African sorts of the red peppers of the market are collected by natives from the wild plants and brought long distances to market.