Dr. Ure states that in its composition tea approaches by the quantity of the nitrogen it contains to animalized matter, and it seems thereby qualified, according to Liebig, to exercise an extraordinary action on some of the functions of the human frame, especially the secretion of bile. Peligot, in a paper on the chemical combinations of tea, read before the Paris Academy of Sciences, stated that it contains essential principles of nutrition, far exceeding in importance its stimulating properties, and showed that it is, in every respect, one of the most desirable articles of general use. One of his experiments on the nutritious qualities of tea, as compared with soup, was decidedly in favor of the former.
The effects of tea on the human system, are, first, stimulant and then narcotic, according to the strength of the beverage. In moderation tea is an excellent diluent; it promotes digestion, and stimulates the renal glands. The constant use of tea, however, in large quantities, especially by persons living on a poor vegetable diet, is not favorable to physical strength or nervous energy; and to persons engaged in sedentary employments, and imperfectly alimented, the frequent imbibing of tannin (for tea contains about 40 per cent.), has a decided and manifest pernicious effect. How far the excessive use of strong tea in China, by alternately elevating and depressing the nervous system, may have led to the craving desire for opium as a counter-stimulant, is deserving of consideration.
Dr. Adam Smith, in a paper read a few years ago before the Society of Arts, recommends the use of tea in the following cases:—After a full meal, when the system is oppressed; for the corpulent and the old; for hot climates, and especially for those who, living there, eat freely, or drink milk or alcohol; in cases of suspended animation; for soldiers who, in time of peace, take too much food in relation to the waste proceeding in the body; for soldiers and others marching in hot climates, for then, by promoting evaporation and cooling the body, it prevents in a degree the effects of too much food, as of too great heat.
There is no doubt that tea acts differently on various individuals. In some it is highly stimulant and exhilarating; in others its effects are oppression and lowness of spirits. It has been remarked that all tea-drinking nations are essentially of a leuco-phlegmatic temperament, predisposed to scrofulous and nervous diseases. The Chinese, even the degraded Tartar races amongst them, are weak and infirm, their women subject to various diseases arising from debility. Although their confined mode of living, and want of the means of enjoying pure air and exercise, materially tend to render them liable to these affections; still their immoderate use of strong tea, taken, it is true, in very small quantities at a time, but repeatedly, greatly adds to this predisposition. Although tea may in general be considered a refreshing and harmless beverage, yet in some peculiar cases it is decidedly injurious; and many diseases that have baffled all medical exertions have yielded to the same corrective means, so soon as the action of tea has been suspended.
The Eclectic Medical Journal, Vol. XXXIV, 1874, was edited by John M. Scudder, M.D.