CAMELLIA TRIBE. TEA PLANT. 395 



like manner considered the black tea plant. It is now quite 

 certain, however, that both kinds of tea may be produced from 

 either species, the chief difference between these articles being 

 dependent upon the mode in which they are prepared. The 

 black and green teas of the northern district of China, from 

 which the foreign markets are chiefly supplied, are the produce 

 of the Thea viridis ; whilst the teas of both kinds mauufac- 

 tnredin the neighbourhood of Canton, are obtained from the Thea 

 bo/iea. By some botanists these two species are regarded as 

 varieties of the same; each of them is liable to undergo nume- 

 rous variations, under the influence of soil, climate, exposure, 

 &c.; and to these differences, in combination with diversities 

 in the time of gathering the leaves and in the mode of pre- 

 paring them, we are to ascribe the great number of varieties in 

 the product. In the preparation of black tea, the leaves are 

 exposed to air after being picked, but are kept cool until they 

 begin to emit a slight degree of fragrance, apparently in con- 

 sequence of having undergone an incipient fermentation, like 

 that which produces the aroma of hay. They are then roasted 

 at a moderate heat over the fire, until they give out a fragrant 

 smell and become quite soft and flaccid ; after which they are 

 rolled under pressure, again roasted and rolled until the juices 

 are pressed out, and finally dried and twisted between the fin- 

 gers. On the other hand, in order to make green tea, the leaves 

 are roasted as soon as possible after gathering ; and they are 

 exposed in this process to a much higher temperature than that 

 employed for black tea. They are then spread out to cool, and 

 afterwards again roasted at a lower temperature. When cooled 

 a second time, they are of a dark olive colour. In the third 

 roasting, which is the final drying, the heat is again diminished; 

 and it is then that the colour of the leaves changes to that 

 bluish tint, resembling the bloom of fruit, which gives to this 

 tea its peculiar appearance. The peculiar properties of green 

 tea are obviously due to a chemical change, brought about by 

 the action of a high temperature on the juices of the leaves ; 

 and it is only in the inferior kinds that any artificial colouring 



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