CHEMICAL, MEDICAL
AND
DIETICAL PROPERTIES.
--------------
Tea in chemistry is a complex mixture of a variety of substances,
including _Theine_, _Tannin_, _Dextrine_, _Glucose_, _Gum_ and an
essential oil known as _Volatile_, 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 vegetable _Caseine_, 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 tannin
_coloring-matter_ and 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 specimens submitted, the results have been as varied.
The average composition in parts range as follows:—
Chemical Constituents. Quantities.
Theine, 3
Tannin, 25
Volatile Oil, 1
Albuminoids, 15
Mineral Matter, 6
Gum and Glucose, 21
Vegetable Fibre, 20
Fatty Substances, 4
Water of Absorption, 5
———
Total, 100
=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
of _Caffeine_ by Runge, who originally found it in Coffee, and later by
Oudry, who extracted an identical substance from tea, to which he gave
the name of _Theine_. Strickler subsequently produced it from cocoa,
naming it _Theobromine_. 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—C_{8}—H_{10}—N_{4}O_{2}—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 it happens 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 a
quantitative 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 determined
whether 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
coloring matter. 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
it decomposes 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
to reason 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 percentage of 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 as _digitalis_ (fox-glove) which, when taken in
overdoses, causes anxiety and inability to sleep. It is a well-known
fact 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.
MEDICINAL EFFECTS.
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 by some 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 colleges and 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 the
mucous membrane, particularly in that of the bowels. In answer to the
question whether _theine_ produces 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 as _kreatine_, the chemical properties of which are
analogous to those of _theine_, 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 a special study, inform
us that the substance known as kreatine is diminished by overwork and
fatigue, and that, therefore, as _theine_ and _kreatine_ are 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 termed _caffeine_ in coffee being identical
with both, serving the same purpose. While Liebig suggests that theine
contributes to the formation of _taurine_, a compound peculiar to bile,
and Lehman found that its administration is followed by a slight
augmentation of urea. It has also been proven that _theine_ and
_quinine_ are 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 and a 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, more
especially, 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 drinking waters. 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,
and to 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.
DIETICAL PROPERTIES.
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:—
FLESH FORMERS.
Constituents. Quantities, in one pound of good Tea.
oz. grs.
Theine, 0. 210
Caseine, 2. 175
Volatile Oil, 0. 52
Fat, 0. 280
Gum, 2. 385
HEAT GIVERS.
Sugar, 0. 211
Fibre, 3. 87
Tannin, 4. 87
Water, 0. 350
Mineral, 0. 350
—— ——
Total, 15 oz. 267 grs.
The use of _theine_ as 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 in their 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 of _theine_, 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 and
enlivens 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 the infirmities 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 particularly observable, 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 the _caffeine_ of coffee and the _theine_ of 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 oxygen and the elements of water, can yield
_taurine_, 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 the _taurine_. 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 that
females, 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.
TEA AS A STIMULANT.
“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
Italian physiologist 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.” While Hazlitt, like Johnson, was a prodigious
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.
TEA AND THE POETS.
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 Bacchanalian and 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:—
“One ounce does all disorders cure.
With two your troubles will be fewer,
Three to the bones more vigor give,
With four forever you will live
As young as on your day of birth,
A true immortal on the earth.”
However hyperbolical this testimony may be considered, it at least
serves to show the high estimation in which the plant was held in China.
The first literary eulogist to espouse the cause of the new drink in
Europe was Edmund Waller, reciting how he became first induced to taste
it. In a poem containing several references to the leaf occurs the
following pregnant allusion to tea:—
“The muses friend doth our fancy aid,
Repress these vapors which the head invade,
Keeping that palace of the soul serene.”
That Queen Anne ranked among its votaries is manifest from Pope’s
celebrated couplet:—
“Though great Anna, whom the realms obey,
Doth sometimes counsel take and—sometimes Tea.”
Johnson did not make verses in its honor, but he has drawn his own
portrait as “a hardened and shameless tea drinker, who for twenty years
diluted his meals with an infusion of this fascinating plant, whose
kettle had scarcely time to cool, who with tea amused the evening, with
tea solaced the night, and with tea welcomed the morning.” While Brady,
in his well-known metrical version of the psalms, thus illustrates its
advantages:—
“Over our tea conversations we employ,
Where with delight instructions we enjoy,
Quaffing without waste of time or wealth
_The soverign drink of pleasure and of health_.”
Cooper’s praise of the beverage has been sadly hackneyed, nevertheless,
as the Laureate of the tea table, his lines are worthy of reproduction
here:—
“While the bubbling and loud hissing urn
Throws up a steaming column, and the cup
_That cheers, but not inebriates_, wait on each,
So let us welcome peaceful evening in.”
That Coleridge, in his younger days, must have liked tea is inferred
from the following stanza:—
“Though all unknown to Greek and Roman song,
The paler Hyson and the dark Souchong,
Which Kieu-lung, imperial poet praised
So high that cent, per cent. its price was raised.”
Gray eulogizing it:—
“Through all the room
From flowing tea exhales a fragrant fume.”
Byron, in his latter years, became an enthusiast on the use of tea,
averring that he “Must have recourse to black Bohea,” still later
pronouncing Green tea to be the “Chinese nymph of tears.” And in
addition to the praises sung to it by English-speaking poets and
essayists, its virtues have also been sounded by Herricken and Francius
in Greek verse, by Pecklin, in Latin epigraphs, by Pierre Pettit, in a
poem of five hundred lines, as well as by a German versifier, who
celebrated, in a fashion of his own, “The burial and happy resurrection
of tea.” In opposition to the “country parson,” who calls tea “a
nerveless and vaporous liquid,” and Balzac, who describes it as an
“insipid and depressing beverage,” the author of “Eothen” records his
testimony to “the cheering, soothing influence of the steaming cup that
Orientals and Europeans alike enjoy.”
------------------------------------------------------------------------