The approximate annual produce of Coca in Peru is about 15,000,000 lbs., the average yield being about 800 lbs. an acre. More than 10,000,000 lbs. are produced annually in Bolivia, according to Dr. Booth of La Paz; so that the annual yield of Coca throughout South America, including Peru, Bolivia, Ecuador, and Pasto, may be estimated at more than 30,000,000 lbs. At Tacna, the _tambor_ of 50 lbs. is worth 9 to 12 dollars, the fluctuations in price being caused by the perishable nature of the article, which cannot be kept in stock for any length of time. The average duration of Coca in a sound state, on the coast, is about five months, after which time it is said to lose flavour, and is rejected by the Indians as worthless. Cuca leaves can be bought in London, but up to the present time it has not come into much use as a beverage, yet it is supplied in Roots’ Cuca Cocoa, which is a combination of Cuca leaves, and the Cocoa bean. There is no doubt whatever in Cuca possessing the qualities ascribed to it, and its application in medicine for many “ills that man is heir to,” is being diligently pursued by physicians all over the civilized world, with very beneficial results, and it is a valuable addition to our pharmacopœia. Johnston, in _The Chemistry of Common Life_,[140] speaking of the general effects of the Coca leaf, says that it “acts differently according to the way in which it is used. When infused, and drunk like tea, it produces a gentle excitement, followed by wakefulness; and, if taken strong, retards the approach of hunger, prevents the usual breathlessness in climbing hills, and, in large doses, dilates the pupil, and renders the eye intolerant of light. It is seldom used in this way, however, but is commonly chewed in the form of a ball or quid, which is turned over and over in the mouth, as is done with tobacco. In this way its action is more gradual and prolonged than when the infusion only is taken. It is also very different in its character, because the constant chewing, the continued action of the saliva, and the influence of the lime or ashes chewed along with it, extract from the leaf certain other active constituents which water alone does not dissolve, when it is infused after the manner of tea.” It contains at least three different constituents; an odoriferous substance, a bitter principle, and a kind of tannic acid. When Cuca is imported into this country the leaves are coated with a resinous substance, like hops have, slightly soluble in water, but wholly in ether—which, on evaporation, leaves a brownish resin, which is powerfully odorous. This scent vanishes if it is exposed to the air for any length of time, and thus is lost one of the most important ingredients of good Cuca—rendering the leaf useless by keeping.