It is interesting to note in this connection that of the five species in the genus _Thea_, only one contains _theine_; of the genus _Cinchonaceæ_, to which coffee belongs, only one contains _caffeine_; while of the many species of Ilex in South America, only three, so far as known, contain caffeine. Chemists assert that theine and caffeine are identical, but physicians know that they differ widely in their physiological and therapeutic effects. PHYSIOLOGICAL AND TOXIC EFFECTS. All of the hollies possess decided physiological action on the human system. _Ilex opaca_ once had a large reputation in Europe and England in rheumatism, gout, cutaneous diseases, and intermittent fever. The young leaves and branches, in France, are fed to cattle, and said to increase the quantity and quality of the milk of cows. Griffith (Medical Botany, 1847) writes of the _cassine_: Another native species, the _I. vomitoria_, of Aiton, appears to be endowed with still more powerful properties. This is a native of the most southern parts of the country, where it is held in high esteem amongst the Indians, who considered it a holy plant, and employed it in their religious ceremonies and councils, to purge their bodies from all impurities. They called both this and the _I. dahoon_ by the name of “cassena.” The leaves, which were the part employed, were collected with great care, and formed an article of trade among the tribes. Dr. B. S. Barton (“Collections,” 38) says of it: “It is thought to be one of the most powerful diuretics hitherto discovered. It is held in great esteem among the Southern Indians; they toast the leaves and make a decoction of them. It is the men alone that are permitted to drink this decoction, which is called ‘black drink.’” These leaves are inodorous, and have a somewhat aromatic, acrid taste. In small doses the decoction acts as a powerful diuretic, and in large ones produces discharges from the stomach, bowels, and bladder. In North Carolina, on the seacoast, the inhabitants modify the deleterious action of their brackish water by boiling a few leaves of cassena with it. (The African kola nut, powdered and added to foul water, is said to purify it. It contains theobromine, an alkaloid analogous to caffeine.) Rafinesque (Medical Botany, 1828) calls it “_Cassine Peragua_” (Schoeph), or _Ilex vomitoria_ (Aiton), and says: This by some is said to be the true cassine of the Florida tribes. But _C. aumlosa_ (Rafinesque), _Ilex cassine_, and _dahoon_, _Viburnum cassinoides_, are all equally so named and used. The leaves are bitterish, sudorific, purgative, and diuretic; vomitive and purgative in strong decoctions, called “black drink.” Said to be useful in gravel, nephritis, diabetes, fevers, and small-pox.