=Tannin=—A large portion of the Tea-extract consists of tannin (tannic acid of a peculiar kind), there being much more in Green teas than in Black, ranging from 13 to 20 per cent. in the former, and 8 to 12 per cent. in the latter, but averaging 12 and 9.50 per cent. respectively, the difference being due to the fact that part of the tannin originally existing in the raw-leaf is destroyed during the process of fermentation to which Black teas are subjected in manipulation. It is a powerful astringent principle, puckering up the mouth when chewed, and to which tea owes its bitterness when overdrawn or boiled, constipating effect on the bowels, and the inky-black color which it imparts to water containing salts-of-iron. But whether it contributes in any degree to the exhilarating, satisfying or narcotic action of the tea has not yet been determined. Johnston thinks it probable that it does exert some such effect from the fact that a species of tannin is found in the Betel-nut, which when chewed produces a mild form of intoxication, but as to whether this property assists or retards digestion is still an unsettled question, the old maxim, “what is one man’s meat is another man’s poison,” being particularly true of this substance. Many persons finding that the use of tea while eating, or immediately after eating, has a soothing effect on their system, while the same persons after drinking coffee, under like circumstances, get nervous, and cannot digest their food properly. As there is no tannin in coffee, it stands to reason that the substance must have some influence on the digestive organs.