Dr. Morton concluded that tea—like other potent drugs—had its proper and improper uses, in moderation it was a mild and pleasant stimulant followed by no harmful reaction but that continued and immoderate use led to serious symptoms including headache, giddiness, ringing in the ears, tremulousness, nervousness, exhaustion of mind and body, disinclination to mental and physical exertion, increased and irregular action of the heart and also dyspepsia.
Dr. Bullard[18] of Boston made inquiry into the subject of poisoning from excessive tea drinking and found that the prominent symptoms were loss of appetite, dyspepsia, palpitation of the heart, headache, nervousness and various forms of functional nervous symptoms of an hysterical or neuralgic character; he found that usually speaking five cups of tea a day on an average were required to produce symptoms of tea poisoning.
A more recent investigator Dr. Wood[19] found in his practice at the Brooklyn Central Dispensary that of 1000 consecutive cases applying for general treatment, 100 or 10 per cent. were found to be “liberal indulgers in tea,” and suffering from its deleterious effects; of those 100 patients:—
45 complained of headache.
20 ” persistent giddiness.
20 ” despondency.
19 ” indigestion.
19 ” palpitation of the heart.
15 ” sleeplessness.
Dr. Wood found that when tea had been used for a considerable period in excess, the symptoms were giddiness, mental confusion, palpitation of the heart, restlessness, sleeplessness, hallucinations, nightmare, nausea, neuralgia, with prostration and anxiety. In three of Dr. Wood’s cases there was a tendency to suicide.
Mr. Jonathan Hutchinson, a great authority thinks that it is only the abuse of tea which is attended with serious consequences. “For my own part I have not the least hesitation in recording the conviction that the development of the tea trade has been in the past and will be in the future a most important aid to the progress of civilisation. Nor do I believe that it will be attended by any serious drawbracks.”[20] But he sounds a note of caution when he says “there can be no doubt whatever that the injudicious use of tea may produce not only alarming attacks of disturbance of the heart, but seriously impair the digestion, and enfeeble the nervous system.”
Sir Andrew Clark, who gave much consideration to the subject, in a lecture delivered at the London Hospital said, “I may remark incidentally that it has always been a matter of surprise to me how it is that we English people do not suffer more than we do from our indulgence in tea, especially tea prepared as it usually is, and taken after a prolonged fast early in the morning. It is a great and powerful disturber of the nervous system, and no one who has any regard for his or her nervous system would take it in that way. Its immediate effect may be all that can be desired. It relieves the malaise which is in itself a sign of warning, and it thus enables the consumer to disregard it. Beware gentlemen, of thus sitting on a safety-valve. Nature provides a warning in most cases of impending disaster, and if you wilfully disregard or stifle them, you do so at your peril. This pernicious habit of taking strong tea after a night’s fast, repeated day after day, week after week, year after year, leaves its stamp on the nervous organism of the individual, and this stamp is handed down, in part at any rate, to the generation that follows.”[21]
Sir Lauder Brunton[22] who has also given much study to the question made some remarks in his Lettsomian Lectures on the “Disorders of Digestion.” He said that tea was very apt to cause a feeling of acidity and flatulence. Sometimes the acidity comes on so soon after the tea taken that it is difficult to assign any other cause for it than an alteration in sensibility of the mucous membrane of the stomach or œsophagus. The effect of tannin he said was to interfere very considerably with the digestion of fresh meat, and there were many people in whom tea taken along with fresh meat will upset the digestion. It did not interfere with the digestion of dried meat such as ham or tongue, the fibres of these have already become shrunk or toughened in the process of curing. He thought that tea at breakfast was not so apt to cause indigestion, but that tea in the afternoon two or three hours after lunch would sometimes bring on acidity almost immediately. A part of the mischief wrought by tea in the lower classes was due to allowing it to infuse for a long time so that a large quantity of tannin was extracted. Another reason was that the poor were accustomed to drink tea very hot. Heat was a powerful stimulant of the heart, and a cup of hot tea was therefore much more stimulating and refreshing than a cold one. The practice, however, of sipping the tea almost boiling was apt to bring on a condition of gastric catarrh. Sir B. W. Richardson was probably more opposed to the practice of tea-drinking than any of our leading modern physicians and as one of the most distinguished medical reformers of recent times his opinion is entitled to carry much weight.
“The common beverage tea,” he says, “is often a cause of serious derangement of health, if not of actual disease. The symptoms of disturbance occur when even the best kind of tea is taken in excess, and almost inevitably from the mixture called ‘green tea’ when that is taken even in moderate quantity.... Tea first quickens, and then reduces the circulation which is the action of a stimulant. But tea does more than this; it contains tannin, and is therefore styptic or astringent in its action from which circumstance it is apt in many persons to produce constipation, and interfere with the function of the liver. In some persons this astringent effect of tea is very bad. It gives rise to a continued indigestion, and what is called biliousness. The most important agent in tea, however, is the organic alkaloid, theine. The alkaloid exercises a special influence on the nervous system, which, when carried to a considerable extent, is temporarily at least if not permanently injurious. At first the alkaloid seems to excite the nervous system, to produce a pleasant sensation and to keep the mind agreeably enlivened and active. The effect is followed by depression, sinking sensation at the stomach, flatulency, unsteadiness with feebleness of muscular power, and not infrequently a lowness of spirits, amounting almost to hypochondriacal despondency. Poor people meet the craving for natural food by taking large quantities of tea. A strong craving for it is engendered which leads to the taking of tea at almost every meal, greatly to the injury of health. Poor women in the factory and cotton districts become actual sufferers from this cause. They are rendered anæmic, nervous, hysterical, and physically feeble. In the better classes of society similar if not such severe injury is effected by tea in those who indulge in it many times a day, and especially in those who indulge in what is called afternoon tea.... The afternoon tea or drum causes dyspepsia, flatulency, nervous depression and low spirits, for relieving which not a few persons have recourse to alcoholic stimulation.... Tea taken late in the evening, except immediately after a moderate meal, interferes with the sleep of most persons by causing indigestion, with flatulency, and sense of oppression. Some are kept awake entirely by the action of the tea on the nervous system; others get off to sleep, but are troubled with dreams, restlessness, and muscular startings. In a few incubus or nightmare is a painful symptom induced by tea.” In old people however, Sir Benjamin Richardson had not noticed such serious results “as persons advance in life the bad effects of tea sometimes pass away or are greatly modified.” But for the generality of people Sir Benjamin certainly felt very strongly about the matter for elsewhere he says “it causes in a large number of persons a long and severe and even painful sadness, there are many who never know a day of felicity owing to this one destroying cause.”[23]
Having generally reviewed the question of injury to health I now come to our own experiments. I first made inquiry into the strength of tea, as commonly consumed, and found that the usual quantity of black tea added was about eight grammes to the 600 cubic centimetres of boiling water. I next approached two well-known firms who kindly supplied me with samples of pure unmixed Indian, Ceylon and China teas.