The problem of tea, coffee and other stimulants is equally instructive. There was a time when primitive men used no stimulants at all, but depended upon those stimulating internal secretions now known to be produced by such glands as the thymus, thyroid, supra-renal capsule, and many others. In time certain plants were found to be stimulating and were instinctively consumed. At present we have become dependent upon them through inheritance from ancestors who survived because they could do better work than the unstimulated. Man now finds a stimulant necessary if he is to live long and work well, and that which has survived the test of centuries is caffeine. Some, chiefly in subtropical zones, take it in coffee; others, mainly those in temperate and cold climates, prefer tea; others, cocoa or chocolate, and its use is universal in civilization. Even among the antagonists of all stimulants may be so excessive as to be harmful. Its moderate use seems to fill all the needs of existence of normal white men in a normal environment and renders unnecessary the other stimulants upon which some nations depend. Opium, for instance, has weeded out the susceptible Hindus so that only immunes are left, and it is not only harmless to them, but the New York Medical Record of January 12, 1901, quotes many authorities showing it to be actually beneficial to those Asiatic races which have known it a long time.* To races newly introduced to opium it is very harmful, as the unfit (i.e., non-immunes) have never been killed off. Filipinos, and indeed all Malays, use the stimulating betel nut (bonga) which they chew up with a little lime and a green leaf (buyo). Its use by adults is universal, and they suffer from its deprivation as we do when deprived of our morning coffee. Other Asiatics use hashish, South Americans cocaine in the coca leaf, Central Africans the fresh kola nut, and so on universally.
* "By countries, the order of importance of our sugar imports in 1903 is: Cuba, Hawaii, East Indies, Porto Rico, British West Indies, other West Indies, Brazil, other South America, Germany, Africa, Austria-Hungary, Philippines, British North America and Central America".
* See also details in G. A. Reid's "Alcoholism".
Hence, we cannot live properly without tea and coffee, and as the tropical natives cannot grow enough for us, we must send down representatives or agents to the tropics to do it for us. It will be to the mutual interests of the native and ourselves. It is not meant to say that no man can live without tea, coffee and similar stimulants, for we all know of men, and great workers, too, who never touch them, but the abstainer is not as efficient as a rule, and is pushed to the wall by those who depend upon them.
The enormous consumption of alcohol in constantly increasing amounts may be partly explained by the fact that it is now proved to be one of the stages of the oxidation of sugar by both plants and animals. Certain ferments or enzymes produced by the cells accomplish this. In one sense, it is the only carbohydrate food we use, and is always present in our bodies. To take it in tiny amounts only relieves us of the necessity of digesting that much starch. Like sugar, it is a poison in strong solution, but unlike sugar is has a selective action on nerve cells and cannot be harmlessly taken in larger amounts than one or two ounces distributed throughout the day. It does seem as though alcohol were becoming necessary, a most curious and disquieting thought. Perhaps its sedative effect at night is as necessary as the stimulation of caffeine in the morning. At any rate, its production consumes immense quantities of starch and sugar from the tropics. At the same time that alcoholic consumption is increasing all over the world, we are witnessing the curious paradox that in many lines of work - engineers, motormen, chauffeurs - total abstinence is becoming necessary on account of the loss of mental clearness which may result in fatal accidents to others. Employers are also finding out that the abstainer does more work and they will not employ a drinker, though they may themselves indulge. The reason for all this is the tendency to drink to excess and paralyze one's powers during working hours. This does not alter the fact that alcohol is becoming a more common beverage for those who can use it.
It is to be noted that the enormous consumption of alcohol and sugar in America is the same phenomenon as the craving for both in the tropics and is partly due to that tropical neurasthenia of migrated types which we have shown to be so common in both places, though in different degrees. Australians also yearly consume 129 pounds of sugar per capita, while the German nation uses 36 and the French but 32. Alcohol and sugar are even interchangeable to a certain extent and replace each other in exhausted states. This fact has recently been seized upon by a few observing physicians who are convinced that the judicious use of sugar in non-poisonous, frequent doses has actually reduced the craving of alcohol in drunkards and may be an aid in the cure of cases not too far gone - an amazing idea which seems destined to have far-reaching results. That is, hot climates may give us the preventives for their own ill effects.