“It is a remarkable fact,” Dr. Hartwig tells us, “that the Indians, who regularly use coca, require but little food, and when the dose is augmented, are able to undergo the greatest fatigues without tasting almost anything else.” Professor Pöppig ascribes this astonishing endurance to a momentary excitement which must necessarily be succeeded by a corresponding collapse, and therefore considers the use of coca absolutely hurtful. Tschudi, however, is of opinion that its moderate consumption, far from being injurious, is, on the contrary, extremely wholesome, and cites the examples of several Indians who, never allowing a day to pass without chewing their coca, “attained the truly patriarchal age of one hundred and thirty years.” The effects of excess in coca chewing are given by Hill in his _Travels in Peru and Mexico_. “The worst that can be said of the coca is its effects upon the health of such of the Indians as use it in excess. It then affects the breath, pales the lips and gums, and leaves a black mark on either side of the mouth. Moreover, after some time, the nerves of the consumer become affected, and a general langour is said to give plain evidence of the sad consequences of excess.” Another writer gives a more depressing picture of the excessive consumer: “The confirmed coca chewer, or Coquero, is known at once by his uncertain step, his sallow complexion, his hollow, lack-lustre black-rimmed eyes, deeply sunk in the head, his trembling lips, his incoherent speech, and his stolid apathy. His character is irresolute, suspicious, and false; in the prime of life he has all the appearances of senility, and in later years sinks into complete idiocy. Avoiding the society of man, he seeks the dark forest, or some solitary ruin, and there, for days together, indulges in his pernicious habit. While under the influence of coca, his excited fancy riots in the strangest visions, now revelling in pictures of ideal beauty, and then haunted by dreadful apparitions. Secure from intrusion he crouches in an obscure corner, his eyes immovably fixed upon one spot; and the almost automatic motion of the hand raising the coca to the mouth, and its mechanical chewing, are the only signs of consciousness which he exhibits. Sometimes a deep groan escapes from his breast, most likely when the dismal solitude around him inspires his imagination with some terrific vision, which he is as little able to banish, as voluntarily to dismiss his dreams of ideal felicity. How the Coquero finally awakens from his trance, Tschudi was never able to ascertain, though most likely the complete exhaustion of his supply at length forces him to return to his miserable hut.”