The alkaloid caffeine, or theine, is found in one or two other plants besides tea and coffee. It occurs in the seeds of _Paullinia sorbilis_, a native of Brazil, and in the leaves of several species of holly, natives of South America, which furnish the Paraguay tea, or Yerba mate, so large an article of consumption in several of the South American republics. The leaves and young shoots, dried, parched, and pulverised, are used for a hot infusion. A kind of cake, called Guarana bread, is made from the seeds of the _Paullinia_, which is highly esteemed in Brazil and other countries when infused, like chocolate, for its nutritive and febrifuge properties, and is sold generally as a necessary for travellers, and as a cure for many diseases. The nutritive and medicinal virtues of all these plants must certainly be attributed in a great degree to the presence of this chemical principle, and to the tannic acid which they also contain. The use of coffee as a beverage has been examined in a chemical and physiological point of view by Professor Lehmann. The general results of his investigations are: 1. That a decoction of coffee exercises two principal actions upon the organism, which are very diverse in character, viz. increasing the activity of the vascular and nervous system, while at the same time it retards the metamorphosis of plastic constituents. 2. That the influence of coffee upon the vascular and nervous system, its reinvigorating action, and the production of a general sense of cheerfulness and animation, is attributable solely to the mutual modification of the specific action of the empyreumatic oil and the caffeine contained in it. 3. That the retardation of the assimilative process brought about by the use of coffee is owing chiefly to the empyreumatic oil, and is caused by caffeine only when taken in large quantities. 4. That increased action of the heart, trembling, headache, &c., are effects of the caffeine. 5. That the increased activity of the kidneys, relaxation of the bowels, and an increased vigour of mental faculties, passing into congestion, restlessness, and inability to sleep, are effects of the empyreumatic oil. Professor Lehmann considers it, therefore, necessary to regard the action of coffee, and, in a less degree, that of tea, cocoa, alcohol, &c., upon the organism, as constituting an exception to the general law, that increased bodily and mental activity involves increased consumption of plastic material. Caffeine, on careful analysis, has been found to contain in 100 parts, 49·80 of carbon, 5·08 of hydrogen, 28·83 of nitrogen, and 16·29 of oxygen. It is inodorous, but has a slightly bitter taste. The proportion in which this principle is found to be present in coffee varies between ¾ lb. and 1¾ lbs. in 100 lbs. of berries.