tThe following comparative analysis of tea, coffee, and the dry kola-nut, are interesting, as show in how nearly they contain the same organic constituents, although in different proportions' 100 Parts of tea 100 Parts of Coffee 100 Parts of Kola contain contain nuts contain Water 12 18.65 Theine 8 1.75 2.13 Caseine 15 18 6.33 Gum 18 9 / Sugar 3 6.5 I 10.67 Starch a trace a trace 42.00 Tannin 26.25 4 Aromatic oil 0.75 0.002 f / 1.52 Fat 4 12 Fiber 20 35 20.00 Mineral substances 5 6.7 8.20 double the amount contained in albumen, fibrine, etc. It is also remarkable as occur ring in Omits very unlike each other, and growing in remote countries, which have by instinct been selected by different nations for the purpose of yielding a slightly exciting and very refreshing beverage (see above). From numerous experiments, it appears that the introduction into the stomach of a small quantity of theine (such as three or four grains, which is the quantity contained in about one-third of an ounce of good tea) has the remarkable effect of diminishing the daily waste or disintegration of the bodily tis sues, which may be measured by the amount of solid constituents contained in the uri nary secretion. And if the waste be lessened, the necessity for food to repair that waste will obviously be diminished in an equal proportion. " In other words," says Professor Johnston, "by the consumption of a certain quantity of tea, the health and strength of the body will be maintained in an equal degree upon a smaller supply of ordinary food. Tea, therefore, saves food—stands to a certain extent in the place of food—while at the same time it soothes the body, and enlivens the mind."—Op. cit. p. 173. It should, how ever, be stated, that the generally accepted view, that theine checks the destruction of the tissues, has been recently called in question by an excellent experimental observer, Dr. Edward Smith, in various memoirs published in the Philosophical Transactions and elsewhere. If double the above quantity of theine (or of the tea containing it)be taken, there is a general excitement of the circulation, the heart beating more strongly, and the pulse becoming more rapid; tremblings also come on, and there is a constant desire to relieve the bladder. At the same time the imagination is excited, the mind begins to wander, visions appear, and a peculiar kind of intoxication comes on; the symptoms 5nally terminating, after a prolonged vigil in a sleep arising from exhaustion. It is not definitely known what changes theine undergoes in the animal economy, but when oxi dized it becomes decomposed into rnethylamine or methylia _hydrocyanic acid and amalic acid The nitrogenous compound allied easeine or gluten constitutes about 15 per cent of the weight of the leaf. As hot water -extracts very little of this substance, a large quantity of this nutritious matter, which forms about 28 per cent of the dried spent leaves is thrown away. Much of it might be dissolved if a little carbonate of soda were added to the boiling water with which the tea is made; and in the brick-tea (the refuse and decayed leaves and twigs, pressed into molds) used by the Tartars, most of this substance is utilized. They reduce the tea to powder, and boil it with the alkaline water of the steppes to which salt and fat have been added, and of this decoction they drink from 20 to 40 cups a day, mixing it first with milk, butter, and a little roasted meal. But without the meal mixed only with a little milk, they can subsist for weeks on this thin fluid food. To the astringent princi ple or tannin, which forms from 13 to 18 per cent of the dried leaf, tea owes its astrin gent taste, its constipating effect upon the bowels, and its property of communicating an ink-like color to water containing salts of iron. Whether this ingredient contributes in any degree to the exhilarating, satisfying, or narcotic action of tea, is not known. Professor Johnston thinks it probable that it does exert an exhilarating effect, from the fact, that a species of tannin is the principal ingredient of the Indian betel-nut, which, when chewed, produces a mild and agreeable form of intoxication.
It is usual to judge of the quality of a tea by its aroma, and by the flavor and color of the infusion which it yields; but to these tests should be added the determination of the amount of soluble matter which it readily yields to boiling water. It is stated by Miller that our ordinary tea contains about 45 per cent of soluble matter; but the independent researches of Davy and Peligot show that boiling water seldom extracts more than one third of the weight of the dry tea; while in J. Lehmann's experiments, only one-sixth
•.5.5 per cent) was extracted. Good tea should, moreover, not yield more than 5 or 6 per cent of ash when incinerated; and a portion of this is probably due to the coloring matter which the Chinese add to the green teas prepared for the foreign market. For this purpose they used to employ a mixture of Prussian blue and gypsum, but indigo is now commonly used, which is probably harmless. Drinkers of green tea who wish to know which of these adulterations they are swallowing, may easily determine the point by the following simple experiment: "If a portion of the tea be shaken with cold water and thrown upon a bit of thin muslin, the fine coloring matter will pass through the muslin and settle to the bottom of the water. When the water is poured off, the blue ;natter may be treated with chlorine, or a solution of chloride of lime. If it is bleached, it is indigo; if potash makes it brown, and afterward a few drops of sulphuric acid make it blue again, it is Prussian blue."—Johnston, op. cit., p. 181, note.
Much has been written regarding the dietetic and medical uses of tea. While some physicians have over-praised its value, others have regarded it as the source of numerous diseases, especially of the nervous system. In his admirable work on Hygiene, Dr. Parkes remarks that "tea seems to have a decidedly stimulative and restorative action on the nervous system, which is perhaps aided by the warmth of the infusion. No depression follows this. The pulse is a little quickened. The amount of pulmonary carbonic acid is, according to Dr. E. Smith. increased. The action of the skin is increased; that of the bowels lessened. The kidney excretion is little affected; perhaps the urea is a little lessened, but this is uncertain, the evidence with regard to the urine being very contradictory." Dr. E. Smith considers that "tea promotes all vital actions." Dr. Parkes regards it as a most useful article of diet for soldiers, and it is well known that cold tea is frequently preferred to beer or cider by sportsmen, reapers, and others engaged in laborious work in hot weather. As a general rule, tea is very prejudicial ta. young children, and is not a suitable drink till growth is completed; and adults of an. irritable constitution, or a leuco-phlegmatic temperament, often suffer from its use. Those with whom tea does not agree will generally find cocoa the best substitute. Old and infirm persons usually derive more benefit and personal comfort from tea than from any other corresponding beverage. In fevers, tea, in the form of a cold weak infusion, is often of great service. In persons of a gouty and rheumatic tendency, and especially in such as are of the lithie acid diathesis (q.v.), weak tea, taken without sugar, and with very little milk, is the best form of ordinary drink. In some forms of diseased heart, tea proves a useful sedative, while in other cases it is positively injurious; and a cup of strong green tea, especially if taken without sugar or milk, will often remove a severe nervous headache. It is nearly as powerful an antidote in cases of opium-poisoning as coffee; and very strong tea has been the means of preserving life, in cases of poisoning by tartar-emetic,, the tannin being in these cases the active agent. It is impossible to speak too strongly against the habit occasionally adopted by students of keeping off their natural sleep by the frequent use of strong tea. The persistent adoption of such a habit is certain to lead to the utter destruction of both bodily and mental vigor.
TEA (ante). The American tea-trade began in 1784, when the first American ship sailed for China. This enterprise was followed in the next year by the dispatching of two vessels, resulting in an importation, direct, of 880,000 lbs.; and in 1786 five vessels brought more than a million pounds. The first direct importation of Japan tea was made in 1868 from Yokohama to Sau Francisco. The intervention of steam in the tea carrying trade occurred first in 1867, when the Pacific mail steamer Colorado made a voyage to Hong Kong and Yokohama, and brought back tea to San Francisco. The time now occupied in the transportation of tea from Japan to New York is 30 to 40 days; and from Shanghai to the same port, 40 to 50 days, via San Francisco and the Pacific railroad. During the war of the rebellion there was levied a war-duty of 25 cents per lb. on tea; which was reduced to 15 cents in 1871, and entirely removed iii the following year. The following table gives the quantity and value of the tea imported into the United States for the fiscal years ending June 30, 1838-79 inclusive: