This section of the book is from "The Complete Herbalist" by Dr. O. Phelps Brown. Also available from Amazon: The Complete Herbalist: The People Their Own Physicians By The Use Of Nature's Remedies.
I ascertained by experiment what was before a preconceived idea, that plants afforded the best agents to antagonize the force of disease, and to re-establish the integrity of any organ or tissue assailed. The discovery was made apparent, however, that indiscriminate selection of medicinal plants was injudicious, and that the curative property of a plant was developed only in proportion as certain essential conditions were provided. These conditions proved to be those necessary to the full health of man, viz., proper climate, air, and food.
The first great essential of a plant which is to be selected for its medical qualities is its nativity. If indigenous to the locality of country wherein found, it is a proper one to select. Plants that are introduced from other countries are lessened or deprived of their virtues, unless they meet in their new home all the essential conditions possessed in their native place.
The geographical location of plants is affected by climatic influences, constituents of soil, heat, moisture, electricicity, etc. The flowers, shrubs, and trees which adorn the plains of India and South America, are not the same with those which clothe the valleys of England and North America. Nor are their medicinal properties the same, however, those herbal products may resemble each other. The plants which flourish on the sea-shore of Great Britain are not the same as those on the coast of Africa, nor are these, again, allied to the maritime vegetation of Chili, South America. Nearly all the beautiful plants which adorn our green-houses are natives of a limited space near the Cape of Good Hope, as are also many of our most beautiful bulbs; but the medicinal properties of all become weakened and changed by transplantation. The curious stafelias, that smell so offensively, are found wild only in South Africa. They are there used for medical purposes by the Aborigines. The trees that bear balsam grow principally in Arabia and on the banks of the Red Sea. The umbelliferous and ciniferous plants spread across Europe and Asia. The Cacti are found only in tropical America, while the lobiatae and cariophyllacea are seldom discovered but in Europe. The peculiar ranges and centres of vegetation, as they are termed, are all owing to chemical, climatic, and electrical influences, and yield their medicinal properties in exact ratio of quality, in accordance with the latitudes or places in which they are indigenous.
From the many facts existing, we must believe that there is not a single disease in man that may not have its remedy or cure, in some herb or other, if we but knew which plant, and where to find it, in this, or that, or any clime or portion of the world -- agreeably to the providence of Nature.
This fact or law is proven in the lower animal kingdom. Who has not often seen not only our familiar domestic animals, but many of the untamed creatures of the forests, fields, and air, seek out some one or peculiar herb, when laboring under sickness or derangement of the functions of its organism?
Truly, Nature has wisely implanted a definite instinct in every organic creature, in order to serve for its health, or for its restoration to health from disease. In man, however, such instinct is not so plainly marked, but to him has been given reason and judgment, and (in some few of the race) a disposition to investigate the laws and mysteries of creation, in order to secure his own highest health and perfection, and to find the means for the healing of his kind, when they have become diseased through ignorance, perversion and violation of the immutable ordinances of Creation.
As the proverb says, "There are sermons in stones, and books in running brooks;" so do we behold volumes of wisdom in all the herbal kingdom -- in every emerald and variegated leaf, in every tinted blossom -- in all, there is a voiceless language, eternally singing significant psalms in praise of "HIM who doeth all things well."
Thus we find that adaptation is the law of the universe -- and nowhere is it more vividly portrayed than in the growth and development of the Herbal world.
It will thus be seen that it is only by carefully studying the physiology or functions, or nature of plants, we can derive instruction for the proper regulation or government of our own organisms. The causes which influence the growth and development of plants, are conditions necessary to be understood, in order to preserve the health or integrity of our systems.