Having long meditated the commencement of a work on the medicinal vegetables of the United States, and feeling myself obligated for its completion, by the instructions from the University in which I have the honor to hold a professorship; it may be proper to make at the outset some general statements of the motives and objects of such a publication.

The Materia Medica, comprising the great body of medicinal agents now in use in the hands of physicians, cannot be said to need an increase in the number of its articles. It is already incumbered with many superfluous drugs; even its active substances are more numerous than can be of use to any one physician, so that it seems quite as susceptible of benefit from reduction as from augmentation in the number of its materials. Under these circumstances, the introduction of new medicines can only be authorized, where from the peculiarity of their powers, or the facility of their acquisition, they are calculated to take the place of others previously in use.

Of our present stock of medicinal agents, collected from various parts of the globe, a few appear to be unique in their powers, and could not in the present state of our knowledge, be superseded by other substances. A number more possess active properties, yet of a kind, for which substitutes might be found among the native productions of almost every country into which they are imported. There are others which possess little activity or value, but which, from a sort of fashion, are still articles of commerce and consumption.

In the management of diseases, the physician requires instruments of determinate power, on the operation of which, he may build definite expectations. Many such are already in his hands. Yet when we consider how small a portion of the vegetable kingdom has been medically examined, there can be little doubt that a vast number of active substances, many perhaps of specific efficacy, remain for future inquirers to discover. In this respect, every successive age is making acquisitions. But a century or two ago, the civilized world were unacquainted with the propertics of ipecacuanha, of jalap, and the Peruvian bark. The powers of digitalis in certain diseases are of very recent observation. At the present day, we are speculating on the probable composition of a vegetable medicine, which cures the gout.

Medicinal substances frequently owe their first introduction to accident. Many have been at first brought up as antidotes for the poison of serpents, as remedies for syphilis, or as specifics against imaginary diseases. Previously to this, they were neglected as useless, or avoided as dangerous. It is a subject of some curiosity to consider, if the knowledge of the present Materia Medica were by any means to be lost, how many of the same articles would again rise into notice and use. Doubtless a variety of new substances would develop unexpected powers, while perhaps the poppy would be shunned as a deleterious plant, and the cinchona might grow unmolested upon the mountains of Quito.

It is the policy of every country to convert as far as possible its own productions to use, as a mean of multiplying its resources, and diminishing its tribute to foreigners. The plants of the United States are various in their character in proprotion to the extent of latitudes and climates, which our country embraces. Among those which have been medicinally investigated, are many of useful properties and decided efficacy. Several departments of the Materia Medica may be amply supplied from our own forests and meadows, although there are others, for which we must as yet depend on foreign countries. We have yet to discover our anodynes and our emetics, although we abound in bitters, astringents, aromatics and demulcents. In the present state of our knowledge we could not well dispense with opium and ipicacuanha, yet a great number of foreign drugs, such as gentian, columbo, chamomile, kino, catechu, cascarilla, canella, &c. for which we pay a large annual tax to other countries, might in all probability be superceded by the indigenous products of our own. It is certainly better that our own country people should have the benefit of collecting such articles, than that we should pay for them to the Moors of Africa, or the Indians of Brazil.

Independent of the frauds of adulteration, which may be practised by savages upon drugs, whose origin is hardly known to Europeans, the embarrassments occasioned by the chances of war and commercial restrictions, form serious objections to an exclusive dependence on foreign medicines. It is but a few years since some circumstances of this sort occasioned a sudden and enormous rise in the price of opium, and a general inquiry, what could be substituted for opium when the usual supplies should have failed.

In a work like the present, although we cannot hope to supply all the desiderata of an indigenous Materia Medica; yet it will be satisfactory to have done something towards an investigation of the real properties of our most interesting plants, and to have facilitated a knowledge of them in those, to whom they may be useful. In a pursuit of this kind, the botanist has views even beyond the physician. To him it is important not only to know what plants have properties, that are eminently useful, but also to know, what are the properties and uses of all the plants which surround him. In proportion as inquiries of this sort are pursued, the natural resources of a country become developed, and its natural disadvantages compensated. We are told that in China every plant is applied to some valuable purpose, and there is scarcely a weed that has not its determinate use. [Macartney's Embassy, vol. ii. chap. II.] A learned author [Sir J. E. Smith.] observes, that "no writer whatever has rendered the natural productions of the happiest and most luxuriant climate of the globe, half so interesting or instructive, as Linnaeus has made those of his own northern country."

Under the title of AMERICAN MEDICAL BOTANY, it is my intention to offer to the public a series of coloured engravings of those native plants, which possess properties deserving the attention of medical practitioners. The plan will likewise include vegetables of particular utility in diet and the arts; also poisonous plants which must be known, that they may be avoided. In making the selection, I have endeavoured to be guided by positive evidence of important qualities, and not by the insufficient testimony of popular report. In treating of each plant, its botanical history will be given; the result of such chemical examinations as I have been able to make of its constituent parts, and lastly its medical history. The botanical account will be found more diffuse than is necessary for exclusive botanists. The chemical inquiries are made chiefly with a view to the pharmaceutical preparations of each plant, or to interesting principles it may contain. Its medical history will contain such facts, relative to its operation on the human system, as are known to me from my own observation, or the evidence of those, who are qualified to form correct opinions on the subject.

I am by no means ambitious to excite an interest in the subjects of this work, by exaggerated accounts of virtues which do not belong to them. Much harm has been in medicine, by the partial representations of those, who, having a point to prove, have suppressed their unsuccessful experiments, and brought into view none but favorable facts. If, from a desire of avoiding error, I have not always been able to establish fully the character of a native vegetable, it will be recollected that many foreign drugs, which have been for centuries in use, have still an unsettled reputation as to their powers and modes of operating.

The figures of the present volume have been engraved and coloured from original drawings, made principally by myself. Dissections of the flower and fruit have been added to each for the use of botanical students. The subsequent portions of the work will be issued as rapidly as is consistent with their faithful execution. At the end will be added an appendix or supplement, containing such facts relative to the plants already published, as may have come to light since their publication.

American Medical Botany, 1817-1821, was written by Jacob Bigelow, M. D.