ADULTERATION AND DETECTION. 137 



FOREIGN OB SPURIOUS LEAVES IN TEA. 



Another reprehensible form of adulteration is the sub- 

 stitution or admixture of foreign or spurious leaves ob- 

 tained 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 Eng- 

 land, 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 com- 

 pared 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 ascer- 

 taining whether these distinctive characteristics are 

 present in the leaves under treatment, it will be found 



