Some roots require slicing and removing fibrous rootless. In general, large roots should be split or sliced when green in order to facilitate drying. Barks of trees should be gathered in spring, when the sap begins to flow, but may also be peeled in winter. In the case of the coarser barks (as elm, hemlock, poplar, oak, pine, and wild cherry) the outer layer is shaved off before the bark is removed from the tree, which process is known as "rossing." Only the inner bark of these trees is used medicinally. Barks may also be cured by exposure to sunlight, but moisture must be avoided. Leaves and herbs should be collected when the plants are in full flower. The whole plant may be cut and the leaves may be stripped from it, rejecting the coarse and large stems as much as possible, and keeping only the flowering tops and more tender stems and leaves. Both leaves and herbs should be spread out in thin layers on clean floors, racks, or shelves, in the shade, but where there is free circulation of air, and turned frequently until thoroughly dry. Moisture will darken them. Flowers are collected when they first open or immediately after, not when they are beginning to fade. Seeds should be gathered just as they are ripening, before the seed pods open, and should be winnowed in order to remove fragments of stems, leaves, and shriveled specimens. The collector should be sure that the plant is the right one. Many plants closely resemble one another, and some "yarbs," contrary to the popular impression, are deadly poison--nightshade (belladonna) and the wild variety of parsnips, for instance. Therefore, where any doubt exists, send a specimen of the entire plant, including leaves, flowers, and fruits, to a drug dealer or to the nearest state experiment station for identification. Samples representative of the lot of drugs to be sold should be sent to the nearest commission merchant, or drug store, for inspection and for quotation on the amount of drug that can be furnished, or for information as to where to send the article. In writing to the different dealers for information and for prices, which vary greatly, it should be stated how much of a particular drug can be furnished and how soon this can be supplied, and postage should always be inclosed for reply. The collector should bear in mind that freight is an important item, and it is best, therefore, to address the dealers accessible to the place of production. The package containing the sample should be plainly marked with contents and the name and address of the sender. When ready for shipment crude drugs may be tightly packed in burlap or gunny sacks, or in dry, clean barrels. Burdock root brings from three to eight cents per pound, and seed five to ten cents. About fifty thousand pounds of the root is imported annually, and the best has come from Belgium. Of dock roots, about 125,000 pounds are imported annually, at from two to eight cents. The field for the sale of dandelion root is large.