Coca is consumed chiefly in Peru, Bolivia, Colombia, and Brazil. Since 1863—the time from which our first efforts to popularize it date—its use has rapidly become general, and it may be stated that to-day it is known and used in all civilized countries. [Illustration] [Illustration] CHAPTER III. PHYSIOLOGY OF COCA. It is to empiricism and that alone that we owe our first knowledge of the physiological action of Coca. There is nothing surprising in that, for empiricism is nothing more, in reality, than unconscious observation. The Indians, who from time immemorial consumed so great a quantity of Coca leaves, did not do so merely from religious sentiment which deified the leaves of Coca, they well knew that they would derive great benefit from its use; they knew it only too well, since it is to that cause that we must attribute the legendary accounts given by the first authors who wrote on Coca. This veneration for Coca arose, as we have seen, from its wonderful qualities. There are indeed, in this direction, some truly extraordinary accounts which should not be dismissed without notice, as they are given in good faith. Unanué, of Lima, relates that at the siege of La Paz, Bolivia, in 1781, only those inhabitants who had taken Coca were able to endure hunger and fatigue. Nearly all of the soldiers perished, deprived, as they were of food and overcome by forced marches, except those who had taken the precaution to provide themselves with Coca leaves. It must not be believed that this prolonged fast, sustained by the use of Coca, wastes the strength and is injurious to the appetite. Indeed, according to the statement of all authors, the Indians who pass an entire day without eating, notwithstanding the hardship of forced marches, content themselves with chewing Coca leaves, and eat very heartily in the evening. "The Indians who accompanied me on my voyage," says Weddel, "chewed Coca leaves all day, neither drinking, eating, nor showing any signs of fatigue. But at evening they replenished their stomachs like men who were completely famished, and I can assure you that I have sometimes seen them devour at one meal more aliment than I could have consumed in two days." We will see, further on, that it is in exciting the cerebro-medullary and nervous muscular functions, in part, and partly in producing a soothing effect on the mucous membrane of the stomach, that Coca produces these wonderful results in the conservation of energy without the tortures of hunger, notwithstanding the deprivation of aliment. After this abstract of the well-known and recognized properties of Coca leaves, we will proceed to the medical study undertaken regarding this subject. In 1850 Niemann discovered the active principle of the leaves of Coca, to which he gave the name of Cocaine, though, in fact, the discovery of this alkaloid should be attributed to Gardeke, who had separated it in 1855 under the name of _Erythroxyline_.