Another reprehensible form of adulteration is the substitution or admixture of foreign or spurious leaves obtained from other plants, which resemble in structure but differ widely in character from the true tea-leaf, such as those of the willow, plum or ash. Millions of pounds of these leaves are annually picked, cured and colored in the same manner as tea in China, and used for the purpose of increasing the bulk and reducing the cost, while in England, particularly, the leaves of the birch, elm, willow, chestnut, poplar and hawthorne have been extensively used for the same purpose. The coloring material used in the latter country differs from that used in China and Japan being still more dangerous and injurious to health. This form of adulteration, however, is trivial when compared with the former one, but, nevertheless, the expert and analyst are frequently called upon to deal with it to a much greater extent than most people imagine. Such foreign leaves in tea may be best detected by their botanical character or by the absence of the special structural marks which distinguish the genuine tea-leaf from that of all other leaves in the vegetable kingdom, for while the true leaf bears a strong resemblance to that of the willow, ash and plum, it varies, however, in size form and structure. The border of the true tea-leaf is more regularly serrated, the serration stopping just short of the stalk, and the venations are very characteristic, the veins running out from the mid-rib almost parallel to one another, but altering their course before the border of the leaf is reached, and turning so as to leave a bare space just within the border of the leaf. So that in making an examination of a sample of tea for the purpose of ascertaining whether these distinctive characteristics are present in the leaves under treatment, it will be found convenient to pour hot water on them so as to soften, uncurl and spread them out more easily, as otherwise considerable difficulty will be experienced owing to the brittleness of the tea-leaves in the dry state. TRUE TEA-LEAVES. ------------------------------------------------------------------------ [Illustration: CHINESE TEA-LEAF.] ------------------------------------------------------------------------ [Illustration: JAPANESE TEA-LEAF.] The leaf of China Green tea is much broader than that of Black in proportion to its length, but not so thick, and somewhat accuminate or curled at the apex, that of Black being elliptical, oblong and flat in shape, long and pointed, that of Green being much shorter and rounder in form. ------------------------------------------------------------------------ [Illustration: INDIA TEA-LEAF.] ------------------------------------------------------------------------ [Illustration: CEYLON HYBRID TEA-LEAF.] ------------------------------------------------------------------------ [Illustration: JAVA TEA-LEAF.]