"Tea," says Dr. Hugh Smith, in his Dissertation upon the Nerves, "is very hurtful both to the stomach and nerves. Phrensies, deliriums, vigilation, idiotism, apoplexies, and other disorders of the brain, are all produced by the nerves being thus disarranged and debilitated. If the digestive faculty of the stomach be weakened, the body, failing of recruiting juices, must tend to emaciation, and the whole frame be rendered one system of distress and infirmity. The nerves, being thus deprived of a sufficiency of their animal spirits, must become languid, and leave every sense void of the first means of conveying to the mind the only enjoyments of our temporal existence.
"But if there be any class of persons to whom India tea is more particularly hurtful than to any other, it is that which includes the studious and sedentary, and especially those who are enfeebled with gout, stone, and rheumatism; age, accident, or avocation, cause many persons to be unfortunately ranked amongst those of the latter description. These, from their intensity of thought, want of exercise, injurious position of body, respiration of unwholesome air, and a variety of other causes, have not only their animal spirits exhausted, but their liquids corrupted from the loss of a necessary circulation. With these evils India tea operates as an absolute poison. Indeed, it frequently renders those incurable, who might, by other means, have been relieved.
"When a view is taken of the dismal effects produced by India teas, the mind seems to be bewildered in searching for the cause of using so generally a drug that is so universally destructive. It chiefly originated in a fundamental mistake of physical principles. About the time that India tea was introduced to Europe, a grievous error crept into the practice of medical professors; they falsely imagined that health could not be more promoted than by increasing the fluidity of the blood. This opinion once established, it is no wonder that mankind, with one accord, adopted the infusion of India tea, which was then a novelty to Europe, as the best means of obtaining the above effect. By the advice of Bentikoe chiefly was the pernicious custom of drinking warm liquors, night and day, established. To this man, and the introduction of India tea, may be ascribed that revolution in the health of Europeans which has happened since the last century. The present age, therefore, have great cause to lament, in what they suffer in nervous complaints, that their forefathers did not attend more to the scientific and judicious advice of the illustrious Duncan, Boerhaave, and the whole school of Leyden, who proscribed this error. Although they could not entirely prevent this physical abuse, yet their zealous endeavours did, in some degree, at first impede its progress; but, however, so powerful did novelty plead in favour of India teas, that, at last, general custom and prejudice bore away every barrier that had been erected by these learned and experienced physicians. This error, instead of diminishing, has increased: most valetudinarians are now of opinion that a thick blood is the sole cause of their complaints; with this impression they adopt what they call the diluent beverage of India teas. It can scarcely be imagined how many disorders this practice produces; it may be justly termed the box of Pandora, without even hope remaining at the bottom." Tissot says, "They are the prolific sources of hypochondriac melancholy, which both adds strength to and is one of the worst of disorders." He adds, "with regard to studious men, who are naturally weak and feeble, such warm beverages are more hurtful to them than to others; for they are not troubled with an over thick, but, on the contrary, too thin a blood. You are all aware," continues he, "respectable auditors, that the density of the blood is as the motion of the solids; the fibres of the learned are relaxed, their motions are slow, and their blood, of consequence, thin. Bleed a ploughman and a doctor at the same time; from the first there will flow a thick blood, resembling inflammatory blood, almost solid, and of a deep red; the blood of the latter will be either of a faint red, or without any colour, soft, gelatinous, and will almost entirely turn them to water. Your blood, therefore, men of learning, should not be dissolved, but brought to a consistence; and you should in general be moderate in the article of drinking, and cautiously avoid warm spirituous liquors.