IV. Sometimes the succulent Tea leaves are twisted into cords like packthread, about an inch and a half or two inches long; and usually three of these are tied together at the ends by different-coloured silk threads. These resemble little bavins, one of which might suffice for tea for one person. I have seen them both of green and bohea Tea. * * * * * The Chinese likewise prepare an extract from Tea, which they exhibit as a medicine dissolved in a large quantity of water, and ascribe to it many powerful effects in fevers and other disorders, when they wish to procure a plentiful sweat. This extract is sometimes formed into small cakes, not much broader than a sixpence, sometimes into rolls of a considerable size. That there is only one species of Tea tree, has already been mentioned (SECT. I.) from which all the varieties of Tea are procured. Kæmpfer, who is of this opinion, attributes the difference of Teas to the soil and culture of the plant, age of the leaves when gathered, and method of curing them[43]. These circumstances will severally have more or less influence; though whether they account for all the varieties observable in Tea may be doubted. The bohea Tea trees, now introduced into many botanic gardens near London, exhibit very obvious varieties. The leaves are of a deeper green colour, and not so deeply serrated; the stalk is usually of a darker colour, and the whole shrub appears less luxuriant as represented in the annexed plate of the bohea Tea; but the botanical characters are the same. [Illustration: Bohea Tea.] I infused all the sorts of green and bohea Teas I could procure, and expanded the different leaves on paper, to compare their respective size and texture, intending thereby to discover their age. I found the leaves of green Tea as large as those of bohea, and nearly as fibrous; which would lead one to suspect, that the difference does not so much depend upon the age, as upon the other circumstances. We know that in Europe the soil, culture, and exposure, have great influence on all kinds of vegetables: but the same species of plants differ in the same province, and even in the same district; and in Japan, and particularly along the continent of China, it must be much more considerable, where the air is in some parts very cold, in others moderate, or warm almost to an extreme. I am persuaded that the method of preparation must also have no little influence. I have dried the leaves of some European plants in the manner described (SECT. VI.) which so much resembled the foreign Tea, that the infusion made from them has been seen and drunk without suspicion. In these preparations which I made, some of the leaves retained a perfect curl, and a fine verdure like the best green Tea; and others cured at the same time were more like the bohea[44].