Dr. Halliday adds, “The Siberians denominate the leaves of this plant, when infused in water, Intoxicating Tea; and a weaker infusion is in daily use, especially for treating their neighbours, just as the Europeans do with tea from China.”
Before we quit the consideration of Climate, as being capable of influencing the activity of a remedy, the important fact should not be overlooked, that in India, and other colonies of similar temperature, Mercurial Medicines, in order to produce their beneficial effects, require to be administered to an extent which would prove destructive to the inhabitants of this island.
But of all the circumstances that produce the greatest change in the aspect as well as in the virtues of the vegetable creation, is Cultivation, which may either destroy the medicinal properties of a plant, or raise in it new and most valuable qualities: cultivation converts single into double flowers, by developing the stamens into petals, a change which in many cases destroys their efficacy, as in the camomile, Anthemis Nobilis; for, since all the virtues of this flower reside in the disc florets, it is of course greatly deteriorated by being converted into the double-flowered variety; by the operation of grafting extraordinary changes may also be produced; Olivier, in his travels, informs us that a soft Mastiche, having all the qualities of that resin, except its consistence, which is that of turpentine, is procured by engrafting the Lentisk on the Chian Turpentine tree.
Buffon states that our wheat is a factitious production raised to its present condition by the art of agriculture. M. Virey[[121]] observes, that by suppressing the growth of one part of a plant we may respectively give rise to an increased developement in others; thus are some vegetables rendered eunuchs, or are deprived of seeds by obliteration, and only propagate themselves by slips; such a condition is frequently produced by culture, continued through a long succession of generations; this is the case with the Banana, Sugar Cane, and other fruits that have carefully been made to deviate for a long series of years from their original types, and having been continually transplanted by slips, suckers, or roots, at length only propagate themselves in this way, whereby the roots, as those of the common potatoe, become inordinately developed, drawing to themselves the succulence and nutrition originally possessed by the berries. It seems probable that we may thus have lost many vegetable species; the Tuberes of Pliny, for example, are supposed by Mr. Andrew Knight to have been intermediate productions, formed during the advancement of the Almond to the Peach, or in other words that they were swollen almonds or imperfect peaches; if this conjecture be admitted, it will explain the fact stated by Columella, that the peach possessed deleterious qualities when it was first introduced from Persia into the Roman Empire. If there be any who feel sceptical upon the subject of such metamorphoses, let him visit the fairy bowers of Horticulture, and he will there perceive that her magic wand has not only converted the tough, coriaceous covering of the Almond into the soft and melting flesh of the Peach, but that by her spells, the sour Sloe has ripened into the delicious Plum, and the austere Crab of our woods into the Golden Pippin; that this again has been made to sport in endless variety, emulating in beauty of form and colour, in exuberance of fertility and in richness of flavour, the rarer productions of warmer regions, and more propitious climates! In our culinary vegetables the same progressive amelioration and advancement may be traced; thus has the acrid and disagreeable Apium graveolens been changed into delicious Celery, and the common Colewort, by culture continued through many ages, appears under the improved and more useful forms of Cabbage, Savoy, and Cauliflower. It has been already observed that the alimentary and medicinal virtues are frequently in opposition to each other, and that while cultivation improves the former, it equally diminishes the latter; I shall have occasion to offer some additional facts upon this curious subject, under the consideration of Bitter Extractive; see Note on this Extract, in the article “Tonics.”
THE IGNORANT PREPARATION AND FRAUDULENT ADULTERATION OF MEDICINES.
The circumstances comprehended under this head certainly deserve to be ranked amongst the more powerful causes, which have operated in affecting the reputation of many medicinal substances. The Peruvian Bark fell into total discredit in the year 1779, from its inability to cure the ague; and it was afterwards discovered to have been adulterated with bark of an inferior species; indeed Sydenham speaks of the adulteration of this substance before the year 1678; he tells us that he had never used to exceed two drachms of Cinchona in the cure of any intermittent, but that of late the drug was so inert, rotten, and adulterated, it became necessary to increase its dose to one, two, or three ounces. The subject is copious and full of importance, and I have taken considerable pains to collect very fully, the various modes in which our remedies are thus deprived of their most valuable properties, and to suggest the best tests by which such frauds may be discovered. Very few practitioners have an idea of the alarming extent to which this nefarious practice is carried, or of the systematic manner in which it is conducted: there can be no doubt but that the sophistication of medicines has been practised in degree in all ages,[[122]] but the refinements of chemistry have enabled the manufacturers of the present day, not only to execute these frauds with greater address, but unfortunately, at the same time, to vend them with less chance of detection. It will be scarcely credited, when I affirm that many hundred persons are supported in this metropolis by the art of adulterating drugs, besides a number of women and children who find ample employment and excellent profit in counterfeiting Cochineal with coloured dough, Isinglass with pieces of bladder and the dried skin of soles, and by filling up with powdered Sassafras the holes which are bored in spice and nutmegs, for the purpose of plundering their essential oils.
THE UNSEASONABLE COLLECTION OF VEGETABLE REMEDIES.
Vegetable physiology has demonstrated, that during the progress of vegetation most remarkable changes occur in succession, in the chemical composition, as well as in the sensible qualities of a plant; time will not allow me to be prodigal of examples, take therefore one which is familiar and striking,—the aromatic and spicy qualities of the unexpanded flowers of the Caryophyllus Aromaticus (Cloves) are well known to every body, but if the flower-bud be fully developed it loses these properties altogether, and the fruit of the tree is not in the least degree aromatic; so the berries of Pimento, when they come to full maturity, lose their aromatic warmth and acquire a flavour very analogous to that of Juniper. The Colchicum autumnale may be cited as another example in which the medicinal properties of the vegetable are entirely changed during the natural progress of its developement. See also Inspissated Juices, under the article Extract.
THE OBSCURITY WHICH HAS ATTENDED THE OPERATION OF COMPOUND MEDICINES.
It is evident that the fallacies to which our observations and experience are liable with respect to the efficacy of certain bodies, as remedies, must be necessarily multiplied when such bodies are exhibited in a state of complicated combination, since it must be always difficult, and often impossible, to ascertain to which ingredient the effects produced ought to be attributed.