Tea is valuable chiefly for its warming and comforting qualities. Taken in moderation, it acts partly as a sedative, partly as a stimulant, arresting the destruction of tissue, and seeming to invigorate the whole nervous system. The water in it, even if impure, is made wholesome by boiling, and the milk and sugar give a certain amount of real nourishment. Nervous headaches are often cured by it, and it has, like coffee, been used as an antidote in opium-poisoning.
Pass beyond the point of moderation, and it becomes an irritant, precisely in the same way that an overdose of morphine will, instead of putting to sleep, for just so much longer time prevent any sleep at all. The woman who can not eat, and who braces her nerves with a cup of green tea,—the most powerful form of the herb,—is doing a deeper wrong than she may be able to believe. The immediate effect is delightful. Lightness, exhilaration, and sense of energy are all there; but the re-action comes surely, and only a stronger dose next time accomplishes the end desired. Nervous headaches, hysteria in its thousand forms, palpitations, and the long train of nervous symptoms, own inordinate tea and coffee drinking as their parent. Taken in reasonable amounts, tea can not be said to be hurtful; and the medium qualities, carefully prepared, often make a more wholesome tea than that of the highest price, the harmful properties being strongest in the best. If the water is soft, it should be used as soon as boiled, boiling causing all the gases which give flavor to water to escape. In hard water, boiling softens it. In all cases the water must be fresh, and poured boiling upon the proper portion of tea,—the teapot having first been well scalded with boiling water. Never boil any tea but English-breakfast tea; for all others, simple steeping gives the drink in perfection.
A disregard of these rules gives one the rank, black, unpleasant infusion too often offered as tea; while, if boiled in tin, it becomes a species of slow poison,—the tannic acid in the tea acting upon the metal, and producing a chemical compound whose character it is hard to determine. Various other plants possess the essential principle of tea, and are used as such; as in Paraguay, where the Brazilian holly is dried, and makes a tea very exhilarating in quality, but much more astringent.
The use of Coffee dates back even farther than that of tea. Of the many varieties, Mocha and Java are finest in flavor, and a mixture of one-third Mocha with two-thirds Java gives the drink at its best. As in tea, there are three chief constituents: (1) A volatile oil, giving the aroma it possesses, but less in amount than that in tea. (2) Astringent matter,—a modification of tannin, but also less than in tea. (3) Caffeine, now found identical with theine, but varying in amount in different varieties of coffee,—being in some three or four per cent, in others less.
The most valuable property of coffee is its power of relieving the sensation of hunger and fatigue. To the soldier on active service, nothing can take its place; and in our own army it became the custom often, not only to drink the infusion, but, if on a hard march, to eat the grounds also. In all cases it diminishes the waste of tissue. In hot weather it is too heating and stimulating, acting powerfully upon the liver, and, by producing over-activity of that organ, bringing about a general disturbance.
So many adulterations are found in ground coffee, that it is safest for the real coffee-lover to buy the bean whole. Roasting is usually more perfectly done at the grocers', in their rotary roasters, which give every grain its turn; but, by care and constant stirring, it can be accomplished at home. Too much boiling dissipates the delicious aroma we all know; and the best methods are considered to be those which allow no boiling, after boiling water has been poured upon it, but merely a standing, to infuse and settle. The old fashion, however, of mixing with an egg, and boiling a few minutes, makes a coffee hardly inferior in flavor. In fact, the methods are many, but results, under given conditions, much the same; and we may choose urn, or old-fashioned tin pot, or a French biggin, with the certainty that good coffee, well roasted, boiling water, and good judgment as to time, will give always a delicious drink. Make a note of the fact that long boiling sets free tannic acid, powerful enough to literally tan the coats of the stomach, and bring on incurable dyspepsia. Often coffee without milk can be taken, where, with milk, it proves harmful; but, in all cases, moderation must rule. Taken too strong, palpitation of the heart, vertigo, and fainting are the usual consequences.
Cocoa, or, literally, cacao, from the cacao-tree, comes in the form of a thick seed, twenty or thirty of which make up the contents of a gourd-like fruit, the spaces between being filled with a somewhat acid pulp. The seeds, when freed from this pulp by various processes, are first dried in the sun, and then roasted; and from these roasted seeds come various forms of cocoa.
Cocoa-shells are the outer husk, and by long boiling yield a pleasant and rather nutritious drink. Cocoa itself is the nut ground to powder, and sometimes mixed with sugar, the husk being sometimes ground with it.
In Chocolate—a preparation of cocoa—the cocoa is carefully dried and roasted, and then ground to a smooth paste, the nuts being placed on a hot iron plate, and so keeping the oily matter to aid in forming a paste. Sugar and flavorings, as vanilla, are often added, and the whole pressed into cakes. The whole substance of the nut being used, it is exceedingly nutritious, and made more so by the milk and sugar added. Eaten with bread it forms not only a nourishing but a hearty meal; and so condensed is its form, that a small cake carried in traveling, and eaten with a cracker or two, will give temporarily the effect of a full meal.
In a hundred parts of chocolate are found forty-eight of fatty matter or cocoa-butter, twenty-one of nitrogenous matter, four of theobromine, eleven of starch, three of cellulose, three of mineral matter, and ten of water; there being also traces of coloring matter, aromatic essence, and sugar. Twice as much nitrogenous, and twenty-five times as much fatty matter as wheaten flour, make it a valuable food, though the excess of fat will make it disagree with a very delicate stomach.