The following chapter has been prepared for this work at my request, by Messrs. Parke Davis & Co., manufacturing chemists, of Detroit, Michigan. I was led to solicit the aid of this firm in the preparation of this portion of my work through the reputation which it has achieved in investigating the medicinal properties of the indigenous flora. Prior to its efforts there had been no systematic attempt in this direction, and such additions to the materia medica as had been made from this source were largely through accidental acquaintance with the medicinal virtues of particular drugs. Messrs. Parke Davis & Co. have for several years been investigating our flora, and while they have found many to be of negative medicinal value, the list of those which have proven serviceable is sufficiently large and important to have made a success of their laudable undertaking. These investigations referred to have, moreover, peculiarly fitted them for the task which they have kindly assumed in connection with this book.
As might naturally have been expected of a country of the dimensions of the United States, with its diversity of climate and soil, and the variety in the physical conformation of its territory, the variety of its medicinal flora is great. Nature has in no sense of the word been remiss in her bestowal of medicinal blessings to the people of this country, and, while we are not fully committed to the belief that she has provided in each section a growth of the drugs best suited to the relief of the diseases peculiar to that section, we nevertheless believe, as the result of no little attention to the subject, that there are indigenous drugs much better suited to many of the diseases of this country than are some of the remedies of foreign extraction, the use of which medical fashion has perpetuated since their original introduction.
There are, moreover, but few of the foreign trees from which we derive our medicines which either do not attain to considerable perfection in the natural state in this country, or which may not be successfully cultivated in some section of our vast territory—in some of its valleys, on some of its mountain-sides, or along some of its watercourses. The actual and possible medicinal wealth of the United States of America is imperfectly appreciated even by medical men. Of late years more attention than heretofore has been directed to our indigenous medicinal flora, and the additions from this source to the materia mediea have been of such a nature as to encourage and stimulate further research in this direction.
In the consideration which we purpose giving the trees of this country which furnish substances employed in medicine we shall not confine ourselves strictly to our indigenous flora, nor to such trees as may be regarded as forest-trees. Some valuable trees have been introduced, and, though they have become naturalized and acclimated, are not strictly entitled to be classed as natives. Some of our flora, too, which are rich in medicinal principles, are not of sufficient size to justify their classification among the forest-trees, that is, in the general acceptation of the term.
In this consideration of trees from a medicinal point of view we shall make no attempt at classification. The difficulties in the way of a perfect classification of drugs are insuperable, and are recognized as such by both physicians and pharmacists. Many efforts, some of which have been exceedingly elaborate, have been made at such a classification, but while each may be tolerably well adapted to the special need desired, none has yet been made which is adapted to the requirements of all. For instance, the classification made by the botanist has nothing especially to commend it to the pharmacist, who has chiefly to do with the physical properties of drugs; while such a one as may be suited to the needs of either of these is of no value to him interested particularly in investigating the physiological action of drugs. Inasmuch, moreover, as the therapeutical properties of medicines cannot be predicated with absolute safety in either their botanical, chemical, or physiological peculiarities, the practical physician requires a classification different from that best suited to the needs of either of the others named. The necessarily brief consideration which we shall give of the medicinal trees of the United States is intended for neither of these professional callings, and we deem it not incumbent on us to attempt a classification adapted to either. Being thus freed from any obligation of the nature indicated, we shall, we think, best subserve the convenience of our readers by a simple alphabetical arrangement of our subjects, and without reference to any of the features selected as bases of classification.
Abies. The genus Pinus of Linnasus is divided into three genera : Pinus, Abies, and Larix. The Abies embraces the firs and spruces, of which there are many varieties. Two of these, A. excelsa and A. Canadensis, are of especial interest, from a medicinal point of view, as furnishing respectively Burgundy and Canada, or Hemlock, pitch. Burgundy pitch is a resinous exudate from the stem of the A. excelsa, or spruce fir. The variety most prized is imported from Switzerland. In its pure state it is quite hard and brittle, and of a yellowishopaque color. Its chief use is as an excipient for various plasters. It is itself lightly rubefacient, and may even produce a slight inflammation in sensitive skins; occasionally also vesication and ulceration may attack the seat of its application. It is useful in rheumatic pains of a chronic nature, and particularly, perhaps, in lumbago. Canada pitch is very closely analogous to Burgundy pitch in its properties, but is more readily softened by heat, a property which sometimes offers an objection to its substitution for the latter.
The bark of the horse-chestnut has been an object of much interest, because of its furnishing a possible substitute for cinchona. The bark of branches of trees of from three to five years of age is considered the best. The claims which have been made for it in this connection cannot, however, be said to have been substantiated, although the bark certainly does possess some degree of antiperi-odic property. It may be given in substance or in the form of a decoction or extract. The dose of the bark is from half an ounce to an ounce.
Aesculus pavia, the red buckeye of the Southern States, yields a fruit which is actively poisonous, producing symptoms analogous to those caused by strychnia. It has not been utilized to any extent in medicine.
This tree, popularly known as the " Tree of Heaven," which has been of late years cultivated to some extent in this country as a shade-tree, has valuable medicinal properties. The bark is a very active anthelmintic, its administration being followed by copious stools, with which are usually associated traces of the worm (tapeworm) when it is present in the intestines. The dose for this purpose is about thirty grains.
The bark, or its fluid extract, has also been used with good effect in nervous affections, such as nervous palpitation of the heart, hiccough, etc., and in spasmodic asthma.
The bark of the root of the common, or smooth, alder is possessed of alterative properties, and is also astringent and emetic. It is quite a popular domestic " blood-purifier," and has even received favorable mention as a remedy in scrofula by the medical profession.
The bark and the berries of the black alder both contain the medicinal principle of the shrub. It is recommended as a tonic and alterative, and enters largely into the proprietary alterative compounds on the market. It has been proposed as a substitute for Peruvian bark, but it cannot supply the place of the latter, except possibly as a tonic and stomachic in dyspepsia. The dose of the powdered bark is about a teaspoonfuL A preferable form of administration is the decoction made by boiling two ounces of the bark in three pints of water, down to a quart. One or two wineglassfuls of this is a dose.
This is a member of the Abies family, already referred to, and is the source of Canada balsam
This beautiful tree takes its common name from the acid taste of its leaves, which are used by hunters to allay thirst, and form also a pleasant, cooling drink in fevers.
The properties of this tree reside in its bark, and are described as stimulant diaphoretic. The bark is used in chronic rheumatism and in cutaneous eruptions. In some parts of the country it has a reputed value as a remedy in syphilis. The berries also contain a certain percentage of the medicinal principle of the tree, and a spirituous infusion of them is said to relieve the pain of a carious tooth when applied to the cavity. The bark may be administered either.in the form of a fluid extract or in decoction.
Both the leaves and the bark of the hickory are medicinal. They are possessed of very decided tonic properties, and, when given in the form of infusion, are valuable in atonic dyspepsia, besides possessing also antiperiodic properties sufficiently marked to make them valuable both as a preventive and curative of ague.
This tree is also variously known as black birch, cherry birch, and mountain mahogany. It is remarkable for the aromatic flavor of its bark and leaves, which, in the form of an infusion, are an agreeable and gently stimulating diaphoretic. It yields an oil which analysis has shown to be identical with the oil of wintergreen.