CHAPTER VIII.CHEMICAL, MEDICALANDDIETICAL PROPERTIES.
Tea in chemistry is a complex mixture of a variety of substances, includingTheine,Tannin,Dextrine,Glucose,Gumand an essential oil known asVolatile, which, together with a portion of the ash, pass into the solution when tea is infused. Being a leaf it also contains some woody fibre, the quantity of which as determined by Mulder, ranges from 17.1 in Green to 28.3 per cent. in Black teas. According to Peligot, whose admirable investigation of tea ranks as a chemical classic, it also contains a large quantity of legumen, a nitrogenous substance, sometimes termed vegetableCaseine, the percentage of which, as given by Peligot, is about 15 per cent. in tea in its usual commercial state. The woody fibre, legumen, some tannincoloring-matterand a certain quantity of the ash make up mainly the portion of the leaf which is not soluble in boiling water. In its commercial state tea is not subject to much irregularity in a hygrometric condition, there being only about 8 per cent. of moisture in it, which may fall to 6 or rise to 10 per cent. from outside causes.
Tea has been analyzed by many other chemists, but owing to a difference in the variety, character, quality, age, color and methods of preparation of the specimenssubmitted, the results have been as varied. The average composition in parts range as follows:—
Theine—Is the alkaloid of tea and is the substance to which it owes its refreshing and stimulating properties. It is a crystallizable matter, soluble in water, very bitter to the taste and characteristic alike of both tea and coffee, being to these beverages what quinine is to bark, and with the base of cocoa which has recently received the name of “theobromine,” it is also closely related. It is further remarkable as occurring in many other plants dissimilar in structure and character, grown in remote countries, but yet selected by the inhabitants on account of their yielding a slightly exciting and refreshing beverage, and to the presence of which the peculiar physiological action of tea on the animal economy is attributed. It was first discovered under the name ofCaffeineby Runge, who originally found it in Coffee, and later by Oudry, who extracted an identical substance from tea, to which he gave the name ofTheine. Strickler subsequently produced it from cocoa, naming itTheobromine. These bodies are evidently related to uric acid as like it, when exposed to the action of nitric acid and ammonia they yield a purple coloring matter, technically termed murioxide.
Theine is a substance which crystallizes very beautifully, forming white, silk-like crystals containing an atom of water of crystallization, the specific gravity of which is 1.23 at 1°C., and the 9 water of crystallization is not altogether evaporated by a temperature of 150°. As deposited from aqueous solutions it still contains an atom of water, but as deposited from solutions in alcohol or ether, or when sublimed it is anhydrous. It is much more soluble in hot than cold water or in alcohol or ether, and according to Peligot, one part of theine dissolves in 300 parts ether or in 93 parts water at ordinary temperatures. It is a base of the same class as aniline and urea, that is to say, it will combine with acids yielding crystalline compounds, but never neutralizing an acid. With chloride of platinum, chloride of gold and corrosive sublimate, the hydrochlorate of theine enters into combination, forming a double salt with each. As will be manifest from its formula—C8—H10—N4O2—theine is one of the most highly nitrogenous substances known to chemists, and connected with this high percentage of nitrogen (almost double that formed in any other albuminous substance) is its property of yielding an abundance of cyanides when fused with soda lime, which property distinguishes it from a number of organic bases, such as piperine, morphine, quinine and cinchonine. With the base of cocoa—which has received the name of theobromine—theine is also closely related, being nothing more than methylated theobromine. Strecker having produced it from theobromine by acting upon a silver derivative with iodide of methyl, in a sealed tube heated at 100°. Theine exists in tea, not in the free state, but in the form of tannate of tea, which appears to be dissolved by the excess of tannic acid contained by the tea leaf, and so ithappens that the theine makes its appearance in the infusion instead of remaining in the exhausted leaves. The proportion of theine in tea has been variously given by different chemists. Mulder finding 0.43 per cent. in Green tea and 0.46 in Black, while Stenhouse found 1.05 and 1.27 in Green and Black respectively. Peligot found 2.34 and 3.0, and Zoller, whose research is comparatively recent, found 3.94 per cent. of theine in India tea. But it would be a mistake to regard these varying results as showing that the quantity of theine in tea is variable, as they serve only to illustrate the difficulties which stand in the way of aquantitative extraction of the theine, and the imperfection of the earlier methods. In Peligot’s paper, these difficulties are referred to, and by making an attempt to extract the theine from a sample of tea the chemist acquires a sense of the truth of them. The experiments of the latter, however, being of great interest to chemists merits a somewhat detailed description. He began by determining the total amount of nitrogen contained in the dried leaves of different kinds of China tea at 110°, finding 6.15 per cent. in 100 parts of Oolong, 6.58 in Congou, and 6.30 in Green tea, while from one sample of India he extracted only 5.10 per cent., proportions six times greater than had been heretofore obtained by any previous analysis. Next testing every soluble substance for nitrogenous matter, he proceeded by successive eliminations to ascertain the quantity of theine in 27 other different samples and found that Green teas contained on an average 10 per cent. of water, and Black only 8 per cent., and also that the latter contained about 43.2 of matter soluble in boiling water while the former averaged as high as 47.1, and that this soluble matter yielded only 4.35 of nitrogen in Black teas, and 4.70 per cent. in Green. It remaining to be determinedwhether this large percentage of nitrogen was wholly due to the theine or in part to some other principle, he next found that the precipitate with sub-acetate of lead contained no apparent quantity, and then testing the theine by a modification of Mulder’s process obtained from Green tea an average of 2.48 per cent., and from a mixture of Green and Black 2.70. But greatly as these quantities exceed those of all other chemists, they were still unable to account for the whole amount of nitrogen found in the infusion, so by adding mere acetate of lead and ammonia, separating them by filtration, and passing through it a current of sulphuretted hydrogen to precipitate the lead, and evaporating the liquid with a gentle heat he obtained an abundant supply of crystals of theine. This supply he still further increased by re-evaporation until the whole amounted to 3.48 per cent. of the entire. There still remaining a syrup containing some theine it was precipitated with tannic acid, the result being added to that already crystallized it yielded a total of 5.84 from Green tea in the natural state and 6.21 in the dried leaf. These experiments being further continued by boiling the exhausted leaves with potash, it showed a presence of caseine to the extent of 28 per cent. of the mass, the proportion of the latter substance in the raw leaf being only 14 to 15.
Theine is extracted from tea by boiling a quantity of the leaves in a considerably larger quantity of distilled water and the liquor squeezed out of the leaves which are to be boiled with a fresh quantity of water and again subjected to pressure, the process being repeated a third time. The several portions of the infusion expressed from the leaves are put in the same vessel, mixed together thoroughly and treated with an excess of acetate of lead and ammonia, which precipitates the tannin and coloringmatter. The liquor is next filtered and the filtrate evaporated down to a small bulk, first over a naked flame and afterwards in a water bath, and on being allowed to cool the solution will deposit crude theine which is removed by filtration, and the filtration nearly dried up in the water bath, and the residue boiled with alcohol, which dissolves the theine out of it. From this hot alcoholic solution theine crystallizes on cooling, a final purification being effected by crystallization from ether and decolorizing with animal charcoal. A simpler but less effective method is to place the dust of finely powdered tea-leaves, or an evaporated watery extract on a watch glass and cover it with a paper cone and hold it over a spirit lamp or gas jet the vapor arising from the glass condenses on the interior of the cone and forms small crystals of theine. Concentrated sulphuric acid dissolves theine in the cold without the production of color, but if the alkaloid be treated with nitric acid evaporated to dryness, and the reddish-yellow residue moistened with a little ammonia it turns a splendid purple color. Again, if a solution of theine be evaporated with chlorine on a watch glass a reddish-brown residue is obtained, which if again treated with the vapor of ammonia it becomes a deep violet of which the chief precipitants will be phosphoric acid, iodine and platinum, forming a yellow and brown precipitate respectively.
Theine having no odor and only a slightly bitter taste it obviously has very little to do with the flavor of tea. It is, however, considered a very valuable constituent on account of the large percentage of nitrogen which it contains and to which is attributed the peculiar physiological action of tea on the animal economy, but what changes it undergoes in the human system has not yet been determined. When oxydized artificially itdecomposes into methleamic (hydrocyanic) acid, a nitrogenous compound closely allied to caseine or gluten, and as hot water extracts but very little of this substance a large amount of it is wasted in the ordinary infusion, which might otherwise be saved by the addition of a little carbonate of soda to the water in preparing it.
Tannin—A large portion of the Tea-extract consists of tannin (tannic acid of a peculiar kind), there being much more in Green teas than in Black, ranging from 13 to 20 per cent. in the former, and 8 to 12 per cent. in the latter, but averaging 12 and 9.50 per cent. respectively, the difference being due to the fact that part of the tannin originally existing in the raw-leaf is destroyed during the process of fermentation to which Black teas are subjected in manipulation. It is a powerful astringent principle, puckering up the mouth when chewed, and to which tea owes its bitterness when overdrawn or boiled, constipating effect on the bowels, and the inky-black color which it imparts to water containing salts-of-iron. But whether it contributes in any degree to the exhilarating, satisfying or narcotic action of the tea has not yet been determined. Johnston thinks it probable that it does exert some such effect from the fact that a species of tannin is found in the Betel-nut, which when chewed produces a mild form of intoxication, but as to whether this property assists or retards digestion is still an unsettled question, the old maxim, “what is one man’s meat is another man’s poison,” being particularly true of this substance. Many persons finding that the use of tea while eating, or immediately after eating, has a soothing effect on their system, while the same persons after drinking coffee, under like circumstances, get nervous, and cannot digest their food properly. As there is no tannin in coffee, it stands toreason that the substance must have some influence on the digestive organs.
For the estimation of tannin in tea various processes are in use, a tritration by means of a standard solution of gelatine, which depends upon the well-known property possessed by gelatine of forming insoluble compounds with tannin being the most effective, but tedious and difficult. A much more simple and promising method consists in tritrating by means of a standard solution of lead, the point of saturation being indicated by the red color struck by an ammoniacal solution of ferricyanide of potassium, one drop of this solution being capable of coloring one milligram of tannin dissolved in 100 parts of water, the exact strength of the solution of lead being ascertained with a standard solution of tannin. In using the solution of lead, 10 drops of it are first diluted with 9 times its volume in water, and the tea infusion dropped into it from a graduated burette until the indicator strikes a red with the drop of the indicator. The infusion of tea is made by boiling 2 grains of the leaves in water and afterwards diluting it to 250, it being understood that the smaller the quantity of this infusion required to saturate the 10 parts of the lead solution, the higher the percentage of tannin in the sample of tea treated. This test is specially applicable for ascertaining whether Black tea in particular has been mixed with spent leaves. By taking the normal percentage of tannin in pure Black tea at 10 and the percentage of tannin in spent tea as 2, the difference is the extent of adulteration.
There is a great variability in the amount of tannin contained in the different varieties of tea, varying in quantity according to the country of production, kind, quality, and state of growth when picked. In six samples of China Oolong teas recently tested, the percentageof tannin extracted, after an infusion of thirty minutes, averaged only 7.44, an almost similar result being obtained from an examination of the finest Congou-China Green teas, ranging from 11.87 to 14.11 per cent., some Japan samples under the same conditions yielding on an average from 8 to 10. While with a sample of the finest Assam (India) a percentage of 17.73 of tannin by actual weight was extracted after an infusion of only fifteen minutes, two samples of India and Ceylon giving respectively 18.91 and 15.26, proving conclusively that India and Ceylon teas are much more heavily weighted with tannin than China and Japan teas. The percentage of tannin in the extract is also quite irregular, according to the quality of the tea, the ratio of tannin to the extract varying quite uniformly with the value of the tea, the percentage falling and rising with the percentage of the extract and cost of the tea.
Volatile Oil—Is the principle which imparts to tea its peculiar flavor and aroma, and upon the amount contained in the dried leaves depends the strength and pungency of the infusion. It is present only in very small quantities, but is, nevertheless, very potent in its effects, the proportions ranging, according to Mulder, from 0.6 per cent. in Black tea to 0.80 in Green, but averaging 0.75 in all good teas. It is found by distilling the tea with water, is lighter in body than water, citron-yellow in color, resinifying on exposure, solidifying with cold, and exerting a powerfully exciting or stimulating effect on the system. But there being no chemical analysis of this constituent extant, its exact effect on the human system is difficult to define. By some authorities it is claimed to produce wakefulness, acting, it is said, in the same manner asdigitalis(fox-glove) which, when taken in overdoses, causes anxiety and inability to sleep. It is a well-knownfact that Green teas produce these effects, while Black does not, the excessive fermentation to which the latter are subjected in the process of curing, dissipating the volatile oil to a greater extent, or, more properly, altering its general character not only in effect but also in flavor.
Gum or Gluten—If it is necessary to estimate the quantity of gum or gluten in tea, as sometimes happens, evaporate an aqueous decoction of the leaves to an extract, and treat the residue with methylated spirit, filter and wash off with hot water, after which evaporate the solution to dryness, next weighing and burning it to an ash and deduct the mineral residue from the original weight of the leaves. Tea extract also yields a large quantity of ammonia when boiled with potash, and it is probable that this character may prove valuable also in testing the genuineness of tea. Tea leaves under an extraordinary amount of ammonia, when submitted to this test, are found to be remarkably rich in nitrogen, the determination of which is also a means of identification. It may also be here remarked that when tea-leaves have been exhausted by infusion, alcohol is still capable of extracting a considerable amount of soluble matter. This alcohol extract, when infused in boiling water, furnishes a liquor which smells and tastes strongly of tea, which, were it not for the expense of the solvent and trouble attending its separation, could no doubt be profitably employed. A fixed oil composed of equal parts of oleine and stearine, serving many purposes, medicinal, illuminating and others, is extracted from the seeds of the tea-plant in many parts of China and Tartary. The other substances extracted from the tea-leaf consists principally of those which, in various proportions, enter into the composition of all plants and include a modification of constituents analagous to sugar, fat, salts, starch and water.The fibre, tannin, legumen coloring matter and a certain quantity of ash making up mainly the portion of the leaf insoluble in boiling water.
The virtues of tea as a medicine have been extolled from the time of its earliest use as a beverage in China.Chin-nung, a celebrated scholar and philosopher, who existed long before Confucius, and to whom its first discovery is attributed, is claimed to have said of it: “Tea is better than wine, for it leadeth not to intoxication; it is better than water, for it doth not carry disease, neither doth it act as a poison when the wells contain foul and rotten matter;” and Lo-yu, another learned Chinese who lived during the dynasty of Tang, declared that “Tea tempers the spirits, harmonizes the mind, dispels lassitude, relieves fatigue, awakens thought, prevents drowsiness, refreshes the body and clears the perceptive faculties,” while the Emperor Kieu-lung advised all his subjects to “Drink this precious liquor at their ease, as it will chase away the five causes of sorrow. You can taste and feel, but not describe the calm state of repose produced by it.” Again, Ten Rhyne, a botanist and chemist to the Emperor of Japan, in a work published about 1730, states that “Tea purifies the blood, drives away frightful dreams, dispels malignant vapors from the brain, mitigates dizziness, dries up rheum in the eyes, corrects humors, regulates the liver, modifies the spleen, restrains sleep, restricts drowsiness, expels lassitude, is good in dropsy, makes the body lively, cheers the heart and drives away fear.” But of its sanitary effects after its first introduction into Europe there was for a long period much consternation existing, being preposterously praised bysome writers as an incentive to virtue, and as unjustly condemned by others as productive of numerous diseases, more particularly that of causing an increase of nervous complaints, which it would perhaps be more just to attribute to the more complicated state of modern social customs arising from an augmented population and advance in luxurious living, in connection with the more frequent infringement of the natural laws, especially that of turning night into day, and not seldom day into night, as is the too common practice of the votaries of fashion, together with the abuse of stimulants, tobacco and other narcotics.
Its assailants, however, were not very distinguished, but have been quite emphatic in their condemnation. Jonas Hanway, a man whose follies may well be pardoned for his virtues, being, perhaps, the most conspicuous of them. “He looked abroad upon the world, and perceiving that many things went wrong with it, and others no longer presented the same attractive appearance, he remembered them to have had in his youth, he laid to the charge of tea all the evils and disenchantments that oppressed his spirits.” “Men,” he says, “seem to have lost their stature and comeliness and women their beauty, and what Shakespeare had asserted to the concealment of love in this age is more frequently occasioned by the use of tea.” The champions of our “wholesome sage,” who contended that “it was far superior to the boasted Indian shrub,” were but a few of the host who attacked tea as “an innovation pregnant with danger to the health and good morals of the people.” Others, again, although resolute for its banishment from the tea-caddy, were yet willing to accord it a place in the medicine chest. To such complaints echoes were not wanting, the tea-drinkers, in a short time, having it all their own way.
Lettson was the first medical writer who attempted to give the public a reasonable and scientific account of tea, but even his fears of its abuse ran away with his judgment. The poet who commends “the cup that cheers, but not inebriates,” must have been startled if Lettson’s pamphlet ever fell into his hands, at the assertion “that the growth of this pernicious custom (drunkenness) is often owing to the weakness and debility of the system brought on by the daily habit of drinking tea,” and that “the trembling hand seeks relief in some cordial in order to refresh and excite again the enfeebled system, whereby such persons fall into the habit of intemperance.” Here assuredly the exception must have been taken for the rule, that tea may be so abused as to create a craving for alcoholic stimulants is unquestionable, but that at any period of its history its abuse has been so general as to become the main cause of intoxication may be safely denied. On the contrary, it was for a long time looked upon as the great means by which intemperance was to have been banished from society. Again, if there be any truth in this charge, why is it that the Chinese and Japanese, who are the greatest and most inveterate tea-consumers in the world for centuries, using it in season and out, are yet the most temperate? It is, however, admitted that the tremblings and other nervous effects produced by tea on brokers and professional testers, liquor is too frequently resorted to as an offset, and that by the practice of some tea drinkers of the absurd and dangerous Russian and English customs of adding vodki, gin or other alcoholic stimulant to the “cup of tea,” a habit is oftentimes acquired which can never afterwards be relinquished. Neither is it true, as alleged by Lettson, that the use of tea has been the cause of the increase of nervous and kindred complaints in collegesand seminaries. Still, his advice is sound when he states that “tea ought by no means to be the common drink of boarding schools, and when allowed, in moderation, the pupils should at the same time be informed that the constant or too frequent use of tea would be injurious to their health and constitutions. As whatever tends to impair the nerve power and ultimately the digestive organs, in strumuous children particularly, should be by all means avoided.” But if a diminution of the number of inflammatory diseases be one of the consequences of the increased consumption of tea, which is now generally conceded, it is very much in favor of its use, as however distracting nervous diseases may be, they are by no means so fatal as those of an inflammatory nature, more particularly as the former can be almost immediately remedied by relinquishing the use of tea or by simply omitting it from the breakfast for a time, at which meal it is certainly less proper to be used.
The medicinal uses of tea, however, are not many, neither does its chemical analysis shed much light on its action on the human economy, a correct estimate of its particular action thereon having so far not been ascertained. So that before attempting any such estimate it will be necessary to consider that many of its attributed ill-effects may be due as much to the spurious leaves of other plants so frequently mixed with genuine tea-leaves for adulteration purposes, as well as to the deleterious compounds so often used in coloring, for the results of which pure tea is held responsible. The most dispassionate inquirers, however, regard it as a narcotic, the stimulating period of which is most conspicuous and of the longest duration, the active ingredient, theine, being an alkaloid identical with the caffeine of coffee,the medical action of the tea infusion upon the system is the result of the several effects of this alkaloid formed by combination of the theine, tannin, volatile oil, and the hot water. Of these elements theine probably plays the most important part, and like all other potent alkaloids theine is a powerful modifier of the nerve functions, increasing the action of the skin and cooling the body by lessening the force of the circulation, but does not cause any congestion of themucous membrane, particularly in that of the bowels. In answer to the question whethertheineproduces nervousness and wakefulness, reliable authorities answer: No! But that, on the contrary, the effect of theine upon the human system is a calming and soothing one, producing a sense of repose and supplying to the body that which is lost by fatigue.
The experiments made with tea on a number of animals for the purpose of ascertaining its effects on the nervous and muscular apparatus give varying results, the most important being that of lessening the amount of nitrogenous excreta, notably that of the urine, which means to diminish the rate at which nitrogenous substances are oxydized within the body, such action being probably due to the volatile oil, as Lehman found the same oil in roasted coffee to produce the same action in his experiments. There being a substance in the flesh or muscles of all animals known askreatine, the chemical properties of which are analogous to those oftheine, and it is now generally accepted that these substances are most agreeable to the human system as food which most nearly resemble the compound that form the tissues and muscles of the body, while those act as poison whose composition is most different from that of the tissues and muscles on which the life of the body depends. Scientists who have made this subject aspecial study, inform us that the substance known as kreatine is diminished by overwork and fatigue, and that, therefore, astheineandkreatineare chemically about one and the same property, the theory is accepted that the theine in tea supplies best that which is lost to the system by the wear and tear of life, the property termedcaffeinein coffee being identical with both, serving the same purpose. While Liebig suggests that theine contributes to the formation oftaurine, a compound peculiar to bile, and Lehman found that its administration is followed by a slight augmentation of urea. It has also been proven thattheineandquinineare similar in nature, and that on analysis these substances are shown to contain the same proportions of carbon, nitrogen, oxygen and hydrogen, and, as is well known, quinine is about the only remedy used in intermittent and malarial fevers and ague. These facts being settled beyond dispute, it can be readily understood why it is that tea is so soothing and beneficial to those who may feel feverish, tired or debilitated. And while it is not claimed that tea alone will cure fever and ague, it certainly acts as a preventative.
In the early stages of fever it is found very valuable when given in the form of a cold infusion, it being not only considered an excellent diluent at the commencement, but also when administered in the form of “a tincture,” prepared by macerating the leaves in proof spirit and adding a teaspoonful of the mixture to a small cup of water. This preparation is given to the patient at short intervals during the night, after the acute symptoms have subsided, and is often of great benefit during the latter stages. For this purpose, in hospitals and other institutions, the leaves which have been used once for the regular infusion, may be macerated in alcohol anda tincture of sufficient strength obtained at a cheap and economical rate. In a peculiar state of the brain, termed “sthenic excitement,” a condition clearly bordering on inflammation, more especially when produced by alcoholic stimulants, intense study or long-continued application of the mind to any particular subject or literary research, an infusion made from Green tea will quickly act as a salutary remedy. While, on the contrary, in periods of diminished excitement, a morbid vigilance and increased nervous disturbance is certain to follow its use, much better results being produced by small quantities repeated than by large ones in such cases.
In cases of poisoning by arsenic and antimony, fatal results have been prevented by the prompt administration of a strong infusion of tea, its power as an antidote in such cases depending on the tannin decomposing the poisonous substances. While it is nearly as valuable an antidote to poisoning by opium as coffee, it is, however, only useful in combatting the secondary symptoms, and should never be administered in such cases until the stomach pump or other means have removed the opium from the stomach. In some forms of heart disease, tea proves a useful sedative, while in others it is positively injurious. Many cases of severe nervous headache are instantly relieved by a cup of strong Green tea taken without the addition of either milk or sugar, but should be only occasionally resorted to in such cases, it being much better to avoid the cause.
The almost total absence of gouty and calculous diseases in China and Japan is claimed to be attributable to the constant and inveterate use of tea by the inhabitants of these countries, in confirmation of which Prout says: “Persons of a gouty or rheumatic nature, and, moreespecially, those prone to calculous diseases, will find tea the least objectionable article of common drink, but should use it without the addition of sugar and only very little milk. When the water is hard, the addition of a small quantity of carbonate of soda will improve the flavor of the tea at the same time, rendering it a more proper beverage for persons so affected, but should not be taken by them for at least four hours after any solid meal, the addition of the alkali serving to increase the action of the skin as well as to augment its cooling and refreshing properties in the fullest degree.”
Dr. Smith alleges that “tea promotes all vital actions, the action of the skin particularly being increased and that of the bowels lessened, the kidney secretions are also affected, and the urine, perhaps, somewhat diminished, the latter being uncertain.” Other recent authorities agreeing that the direct effect of tea upon the human system is to increase the assimilation of food, both of the heat-giving and flesh-forming kinds, and that with an abundance of food it promotes nutrition, while in the absence of sufficient food it increases the waste of the tissues and body generally. An infusion of cold tea has been known to check violent retching and vomiting, while a very hot one will prove beneficial in severe attacks of colic and diarrhœa, having a specific action on the kidneys and urine. An application of infused tea leaves will subdue inflammation of the eyes produced by cold or other causes, but should be applied only and allowed to remain over night; and people who travel much will find a supply of tea a valuable accompaniment, as it is found to improve the taste and counteract the effects of the most brackish water, proving efficient also in preventing the dysenteric and diarrhetic results produced by the frequent and extreme changes of drinkingwaters. It is for the purpose of qualifying the water expressly that tea is so generally used in China, as very little good drinking water is to be met with in any part of that country.
With brain-workers it has always been a favorite beverage, the subdued irascibility, the refreshed spirits, and the renewed energies which the student so often owes to it, have been the theme of many an accomplished pen. Yet it is impossible to speak too strongly against the not uncommon habit frequently adopted by ardent students when prosecuting their studies far into the night, to resist the claims of nature for repose, and keep off the natural sleepiness by repeated libations of tea. That it answers the purpose for the time being cannot be denied, but the object is often attained at a fearful price, the persistent adoption of such a practice being certain to lead to the utter destruction of the health and vigor of both body and mind. Less injury in such cases will result from the use of coffee, there being this difference between the morbid states of the nervous system produced by coffee and that resulting from tea. The effect of the former generally subsides or disappears entirely on relinquishing its use, while that caused by tea is more permanent and often incapable of being ever eradicated.
That tea does not suit all temperaments, constitutions and all ages is no valid argument against its general use. That it is less adapted to children than adults is admitted; indeed, for very young children it is entirely improper, producing in them, like all narcotics, a morbid state of the brain and nervous system in general. It is also unsuited to those of an irritable temperament as well as for those of a leuco-phlegmatic constitution, such persons illy bearing much liquid of any kind, particularly in the evening, prospering best on a dry diet at all times, andto which young children especially should be strictly confined. Briefly it may be summed up that tea is best suited to persons in health, the plethoric and sanguine, and upon which principle it is the proper diet at the beginning of fevers and all inflammatory complaints. Besides the more obvious effects with which all who use it are familiar, tea saves food by lessening the waste of the body, thus nourishing the muscular system while it excites the nervous to increased activity, for which reason old and infirm persons derive more benefit and personal comfort from its use than from any corresponding beverage. To the question “does tea produce nervousness?” the answer is “in moderation, emphatically No!” One to two cups of tea prepared moderately strong, even when taken two to three times per day will not make any one nervous, but when drunk to excess it undoubtedly will. Tea-testers and experts who are tasting it all the time, day in and day out, for the purpose of valuing it, are frequently made nervous by it, soon recover by a little abstinence. Tea, like liquor and drugs, when taken in moderate quantities, produce one effect, but when used in large and immoderate quantities produce just the contrary result. China and Japan teas, containing more theine and less tannin, are consequently less hurtful and more refreshing than India and Ceylon teas, which contain nearly double the quantity of tannin, the astringent property to which India and Ceylon teas owe the harsh, bitter taste so often complained of in them, and which is undoubtedly the unsuspected cause of the indigestion and nervousness produced by their use.
That the universal employment of tea has displaced many other kinds of food is certain, and regarding its dietical properties much has been written for and against.While some physicians have praised its value as an article of food, on account of the large proportion of nitrogen which it contains, others have as strenuously maintained that it is non-nutritious, and does not serve as a substitute for food, and that the only beneficial properties it contains are due to the milk and sugar added in its use. So that in considering the nourishing effects of tea, the nutriment contained in the milk and sugar certainly must not be overlooked, neither must the powerful influence of the heat of the steaming draught be forgotten. According to the chemical classification of food, the “flesh formers” contained in tea of average quality is about 18, and the “heat givers” 72 per cent., water and “mineral matter” being divided between the residue, the several constituents as they are found in one pound of good tea being as follows:—
The use oftheineas an article of diet has not so far been satisfactorily determined; but that it is a question of no mean interest is obvious when we consider that it is found to exist in so many plants, differing widely intheir botanical origin and yet all instinctively used for the same purpose, by remotely situated nations, for the production of useful, agreeable and refreshing beverages.
By taking the normal temperature of the human body at 98°, it follows that where food is taken into the stomach of a lower temperature than that of the body it must necessarily abstract heat from the stomach and surrounding tissues, so that where the practice of taking cold food becomes habitual depression occurs and the stomach is consequently disordered, and the system must make good this heat lost in raising the temperature of cold food or else suffer. The body demanding food when in an exhausted state, cold food or drink makes an immediate drain upon the system for heat before it can supply material for producing combustion, and the body is thereby taxed to supply heat at a time when it is least fitted for it. It is natural, therefore, that there should be a craving for warm food, and as liquid food is deficient in heat-giving matter, the use of cold drink is more injurious than that of cold food. From other experiments it appears that the introduction into the stomach of three or four grains oftheine, which is the quantity contained in the third of an ounce of good tea, has the remarkable effect of diminishing the daily waste or disintegration of the bodily tissues which may be measured by the quantity of solid constituents contained in the many secretions, and if such waste be lessened the necessity for food to repair that waste will obviously be decreased in corresponding proportions. In other words, says Professor Johnstone, “by the consumption of a certain quantity of tea daily the health and strength of the body will be maintained to an equal degree upon a smaller supply of ordinary food.” Tea, therefore, saves food; stands to a certain extent in place of food, while at the same time it soothes the body andenlivens the mind. While tea, according to Dr. Sigmond, “has in most instances been substituted for spirituous liquors, and the consequence has been a general improvement in the health and morals of the people, the time, strength, and vigor of the human body being increased by its use. It imparts greater capability of enduring fatigue, and renders the mind more susceptible of the innocent and intellectual pleasures of life, as well as of acquiring useful knowledge more readily, being not only a stimulant to the mental faculties but also the most beneficial drink to those engaged in any laborious or fatiguing work.” Dr. Jackson testifying “that a breakfast of tea and bread alone is much more strengthening than one of beefsteak and porter.”
In his admirable work on hygiene Dr. Parker remarks that “tea possesses a decidedly stimulating and restorative action on the human system, no depression whatever following its use, the pulse being a little quickened, and the amount of pulmonary carbonic acid accordingly increased.” From this experiment he regards “tea as a most useful article of diet for soldiers, the hot infusion being potent against heat and cold, and more useful still in great fatigue in tropical countries by its great purifying effect on brackish and stagnant water.” Adding that “tea is so light, easily carried and so readily prepared, that it should form the drink,par excellence, of the soldier in service or on the march, above all its power of lessening the susceptibility to malarial and other influences.” And Admiral Inglefield is quoted as strongly recommending the use of tea to Arctic travelers and explorers, as seamen who surveyed with him in the polar regions after an experience of one day’s rum drinking came to the conclusion that tea was more beneficial to them while undergoing the severe work and intense cold. Under theinfirmities of advancing age, especially when the digestive powers become enfeebled and the size and weight of the body begin perceptibly to diminish, the value of tea in checking the rapid waste of tissue is particularlyobservable, and persons, when very much fatigued, will be sooner refreshed by drinking a cup of moderately strong, good tea, than by drinking wine or spirits of any kind. In allaying or satisfying severe thirst, no beverage will be found as efficacious as a draught of cold tea.
Lettson furnishes a calculation, partly his own and partly from other sources, in which he endeavors to prove how much is, in his view, unnecessarily expended by the poor for tea. But the observations of Liebig, if correct, and in all probability they are, offer a satisfactory explanation of the cause of the partiality of the poorer classes, not alone for tea, but for tea of an expensive and therefore superior quality. “We shall never certainly,” he says, “be able to discover how people were led to the use of hot infusions of the leaves of a certain shrub (tea) or a decoction of certain roasted seeds (coffee); some cause there must be which would explain how the practice has become a necessary of life to whole nations.” But it is still more remarkable that the beneficial effects of both plants on the health must be ascribed to one and the same substance, the presence of which in two vegetables belonging to natural families, the product of different quarters of the globe, could hardly have presented itself to the boldest imagination, recent research having shown in such a manner as to exclude all doubt that thecaffeineof coffee and thetheineof tea are in all respects identical. And without entering into the medical action of this principle, it will surely appear a most startling fact, even if we deny its influence on the process of secretion, that this substance, with the addition of oxygenand the elements of water, can yieldtaurine, the nitrogenous compound peculiar to bile. So that if an infusion of tea contain no more than 1-10 of a grain of theine, and contributes, as has been shown, to the formation of bile, the action, even of a such a small quantity, cannot be looked upon as a nullity. Neither can it be deemed that in the case of non-atomized food or a deficiency of the exercise required to cause a change of matter in the tissues, and thus to yield the nitrogenized product which enters into the composition of bile, the health may be benefited by the use of compounds essential to the production of this important element of respiration. In a chemical sense, and it is this sense alone that theine is in virtue of its composition better adapted to this purpose than all other nitrogenized vegetable principles yet discovered. To better prove how the action of tea may be explained, we must call to mind that the chief constituents of the bile contain only 3.8 per cent. of nitrogen, of which only one-half belongs to thetaurine. Bile contains in its natural state water and solid matter in the proportion of 90 parts of the former to 10 parts of the latter, and if, we suppose, these 10 parts of solid matter to be cholenic acid with 5.87 per cent. of nitrogen, then 100 parts of bile must contain 0.171 of nitrogen in the form of taurine, which quantity is contained in .06 parts of theine, or, in other words, 272 grains of theine can give to an ounce of bile the quantity of nitrogen it contains in the form of taurine. The action of the compound in ordinary circumstances is not obvious, but that it unquestionably exists and exerts itself in both tea and coffee is proven by the fact that both were originally met with among nations whose diet was chiefly vegetable. These facts clearly show in what manner tea proves to the poor a substitute for animal food, and why it is thatfemales, literary persons and others of sedentary habits or occupation, who take but little exercise, manifest such a partiality for tea, and also explain why the numerous attempts made to substitute other articles in its place have so signally failed.
“Life without stimulants would be a dreary waste,” remarks some modern philosopher, which, if true, the moderate use of good tea, properly prepared and not too strong, will be found less harmful than the habitual resort to alcoholic liquors. The impression so long existing that vinous or alcoholic beverages best excite the brain and cause it to produce more or better work is rapidly being exploded, healthier and more beneficial stimulants usurping their place. But while the claims made in favor of the “wine cup” must be admitted, it cannot for a moment be denied that as excellent literary work has been accomplished under the influence of tea, in our own times, particularly when the poet, the essayist, the historian, the statesman and the journalist no longer work under the baneful influence of spirituous stimulants. Mantegaza, an Italianphysiologist of high repute, who has given the action of tea and other stimulants careful study, confirms this claim by placing tea above all other stimulants, his enthusiasm for it being almost unbounded, crediting it with “the power of dispelling weariness and lessening the annoyances of life, classing it as the greatest friend to the man of letters by enabling him to work without fatigue, and to society as an aid to conversation, rendering it more easy and pleasant, reviving the drooping intellectual activity and the best stimulus to exertion, and finally pronouncing it to be one of the greatest blessings of Providence to man.”
Tea was Johnson’s only stimulant, he loved it as much as Porson loved gin, drinking it all times and under all circumstances, in bed and out, with his friends and alone, more particularly while compiling his famous dictionary. Boswell drank cup after cup, as if it had been the “Heliconian spring.” WhileHazlitt, like Johnson, was aprodigious tea-drinker, Shelley’s favorite beverage was water, but at the same time tea was always grateful to him. Bulwer’s breakfast was generally composed of dry toast and cold tea, and De Quincy states that he invariably drank tea from eight o’clock at night until four in the morning, when engaged in his literary labors, and knew whereof he spoke when he named tea “the beverage of the intellectual.” Kent usually had a cup of tea and a pipe of tobacco, on which he worked eight hours at a stretch, and Motley, the historian tells us that he “usually rose at seven, and with the aid of a cup of tea only, wrote until eleven.” And Victor Hugo, as a general rule, used tea freely, but fortifying it with a little brandy. Turning from literature to politics, we find that Palmerston resorted to tea during the midnight sessions of Parliament. Cobden declaring “the more work he had to do the more tea he drank,” and Gladstone himself confesses to drinking large quantities of tea between midnight and morning during the prolonged parliamentary sittings, while Clemenceau, the leader of the French Radicals, admits himself to be “an intemperate tea-drinker” during the firey discussions of debate.
In moderation, tea is pre-eminently the beverage of the twilight hour, when tired humanity seeks repose after a day of wearying labor. Then the hot infusion with its alluring aroma refreshing and stimulating, increasing the respiration, elevating the pulse, softening the temper, producing tranquility in mind and body,and creating a sense of repose peculiarly grateful to those who have been taxed and tormented by the rush and routine of business cares and vexations. What a promoter of sociability, what home comforts does it not suggest, as, when Cowper, on a winter’s evening, draws a cheerful picture of the crackling fire, the curtained windows, the hissing urn and “the cup that cheers?” When, however, tea drinking ceases to be the amusement of the leisure moment or resorted to in too large quantities or strong infusions as a means of stimulating the flagging energies to accomplish the allotted task, whatever it might be, then distinct danger commences. A breakdown is liable to ensue in more than one way, as not infrequently the stimulus which tea in time fails to give is sought in alcoholic or other liquors, and the atonic dyspepsia which the astringent decoction produced, by overdrawing induces, helps to drive the victim to seek temporary relief in spirits chloral or the morphine habit, which is established with extraordinary rapidity. For it is a truth that as long as a person uses stimulants simply for their taste he is comparatively safe, but as soon as he begins to drink them for effect he is running into great danger. This may be stating the case too forcibly for stimulants, but if this rule was more closely adhered to we should have fewer cases of educated people falling into the habit of secret intemperance or morphomania.
The subdued irascibility, the refreshed spirits, and the renewed energies which the student and the poet so often owed to tea has been the theme of many an accomplished pen, eminent writers of all times and all countries considering it no indignity to extol the virtues of this precious and fascinating beverage. What Bacchanalianand hunting songs, cavalier and sea songs,rhapsodies and laudations of other subjects have been to our literature, such was tea to the writers, poets, artists and musicians of China and Japan,theirs being confined to the simple subject—Tea. Each plantation was supposed to possess its own peculiar virtues and excellences, not unlike the vineyards of the Rhine, the Rhone and the Moselle, each had its poet to sing its praises in running rhymes. One Chinese bard, who seemingly was an Anacreon in his way, magnifying the product of the Woo-e-shan mountains in terms literally translated as follows:—