Concerning the adulteration of tea there seems to be considerable difference of opinion, some authorities maintaining that adulteration is common, while others maintain that it is very rare, indeed. There is, however, little doubt that used tea is frequently redried, rerolled, and resold as good tea. Willow leaves, strawberry leaves, and mulberry leaves are said to be added occasionally. Every housewife knows that _good_ tea is expensive. Since the different teas are all from the same species of plant why should there be such a difference in price? The expensive teas consist of the very young leaves and terminal branches and are carefully dried and prepared under special supervision. The young leaves and branches have a more delicate flavor. To determine whether a sample of tea consists of young leaves or not soak it in water, carefully roll out the leaves, and measure them. If the majority of leaves measure an inch or more in length it is a poor quality. It must be remembered that even fair medium qualities are mixed; that is, they consist of mature and immature leaves. The best and most expensive teas are often sold at one hundred dollars per pound. They are never exported, but consumed by high Chinese officials. Imperial tea is prepared under the direct supervision of royal government officials. Tea owes its stimulating properties to an active constituent known as thein, which is in all respects similar to caffein, the active constituent of coffee. The flavor which is developed by the drying process is due to several constituents. Besides these substances tea also contains considerable tannin. Tea consumed in moderate quantities is beneficial rather than otherwise. Its injurious properties are due to the tannin, which affects digestion. If consumed in large quantities for a long time the thein causes nervousness and the tannin causes various dyspeptic conditions. In China some chew the leaves treated with arsenic to improve the complexion. The whitening of the complexion is, however, due to the arsenic and not the tea.