These volatile oils are strongest in new teas, and are gradually wasted by exposure to the atmosphere. Robert Fortune and other travelers in China have stated that the Chinese will not use new teas, but allow them to pass through a sort of "ripening" process. Mr. Crole, speaking probably of the Indian teas with which he was so familiar as a planter and chemist, says that "tea should always be kept for a year before being drank. If the infusion of freshly manufactured tea is drank, it causes violent diarrhea; therefore it should be kept a year before it is consumed, in order to let it mellow." There is no doubt that the more impervious the package containing tea is to the air, the more perfectly the finer qualities of the tea are preserved. If there is a necessity for ripening or mellowing by time, air should be rigidly excluded during that period. As to the keeping qualities of fine teas, in tight packages, we know that they are not spoiled or injured by two years storage in this climate. Tannin is the third important element of the tea leaf, and it varies greatly in percentage in different teas, and increases with the age of the growing leaf. It is the cause of the rasping, puckering, astringent effect upon the tongue and interior of the mouth. Tannin in tea has been a great bugbear with the ill-informed, bit it is not nearly so deleterious as some careless or unscrupulous writers would have us believe. In the first place there is a very insignificant quantity of tannin in properly drawn teas, say in those drawn for not longer than five or eight minutes. The tannin present in a fine Black tea, steeped at a moderate temperature for fifteen or twenty minutes will not harm a delicate stomach. We take quite as much tannin in some fruits, and make no fuss about it. Secondly, if a strong solution of tannin is taken into the stomach and there comes in contact with albuminous or gelatinous foods, it will expend its coagulating power upon such substances. If there are no such substances present, it is the expressed opinion of Mr. Crole (in a discussion upon the chemistry of tea) that the tannin is converted into glucose and other harmless products by the digestive processes. The wild declarations that tea tannin "tans" the coating of the stomach into a leathery condition is without foundation. Even where too prolonged steeping has greatly increased the usual proportion of tannin in tea infusion, milk, when added, neutralizes the coagulating power of the tannin entirely or to such degree as to render it harmless. Professor Johnston thinks it quite probable that tannin takes some part in the exhilarating effect of tea, and in that of the betel-nut of the East. While the astringent influence of strong tannin upon the bowels is regarded as unfavorable, hot tea infusion has with many persons a contrary effect, stimulating the peristaltic movements and antagonizing constipation.