Oolongs are common kinds of black teas, much used for mixing with other sorts. Of the green teas the Gunpowder is round, like shot, with green color and fragrant taste. The Imperial is more loosely rolled than the Gunpowder. Young Hyson is in loose rolls, which easily crumble to the touch; it gives a light green infusion. Old Hyson is the older leaves in the picking for Young Hyson. Twankay consists of mixed and broken leaves, and is of inferior quality. Japan teas are both colored and uncolored, and come from Japan; they are very largely consumed in this country. The chemical composition of a fair sample of tea is; Theine, 1. to 3. per cent.; caseine,[11] 15.; gum, 18.; sugar, .3; tannin, 26.; aromatic oil, .75; fat, 4.; vegetable fiber, 20.; mineral substances, 5.; and water, 5. per cent. The tannin is an astringent, while the theine acts as a gentle excitant upon the nervous system. This is probably enhanced by the warmth of the infusion. The best authorities agree that tea is a valuable article of diet for healthy, grown people. It however is not suitable for children until growth is completed. Adults with irritable constitutions may be injured by tea-drinking. Tea is the solace of old age. Cibber[12] wrote: “Tea! thou soft, thou sober, sage and venerable liquid … thou female tongue-running, smile-smoothing, heart-opening, wink-tippling cordial, to whose glorious insipidity I owe the happiest moments of my life, let me fall prostrate.” Waller[13] truthfully says: “Tea doth our fancy aid, Repress those vapors which the head invade And keep the palace of the soul.” Tea is extensively adulterated in many ways. In China exhausted tea leaves and foliage of other trees are employed by millions of pounds each year. Willow leaves are among the principal ones used for mixing with tea. A British consul once related that at Shanghai there were at one time 53,000 pounds of willow leaves in preparation to be sold as tea. Mineral matters are used to color or “face” the tea. “The common test,” states Mr. Felker, in his work “What the Grocers Sell Us,” “is by infusion; this is poured off the leaves and examined for color, taste, and odor, all of which are characteristic.… Impurities like sand, iron filings and dirt may be seen among the leaves or at the bottom of the cups. The leaves, too, betray by their coarseness and botanical character, the nature and quality of the tea, for although the leaves of the genuine tea differ much in form and size, yet their venation and general structure are very distinctive.… ‘Lie tea,’ used to adulterate Gunpowder tea, consists of tea dust mixed with mineral substances, starch and gum, and then formed into little masses resembling tea.” Large tea houses employ professional tea tasters who make steepings and judge upon the flavor, purity, etc.