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.
Dependent upon the causes I have already named, the plants, also, may lose their medicinal virtues; while much will be owing to the season of the year when they are gathered, in order to adapt them to medico-chemical purposes.
For instance, in the Spring of the year the common Nettle plant may afford a palatable food for man; but if selected at a later period, instead of serving as a savory vegetable, or purifier of morbid elements from the blood and system of man, might be converted into or act as a virulent or dangerous poison upon his organism.
In China the Ginseng (so called from the two Chinese words gen sing, "first of plants") plant or root is regarded -- weight for weight -- as silver, for medicinal purposes; whereas the same herb grown in America or other countries, does not possess a tithe of the value of the Chinese production for healing purposes.
The American chamomile, though in all respects the same as the European, is positively inert in its medicinal qualities.
There must be, therefore, I repeat, a combination of influences to insure the full development of perfection of any plant. There must be not only internal but external stimuli, to develop the virtues of the herb. The external, as we have seen, consist of certain nutritious matters contained in the soil, water, atmospheric gases, electricity, light, and heat, besides the elements of oxygen, both in its combined or simple form, nitrogen, etc.
If we take a stem cut from a pine tree, in the forests of North Carolina, and place it in contact with the trunk of a healthy growing pine, the former would destroy the latter in the course of the season. The worms generated in the severed or decayed stem will pass to the living tree, and rapidly cause its destruction.
Any farmer knows that if the lordly oak be felled in June it will pass into a state of decay in the course of from four to eight weeks; but if it be cut down at a proper season (which is in Fall and early Spring, when the tree is nearly destitute of sap), it affords the best timber for the building of ships. It may be of interest, also, to state that at such times the transplantation of trees should be made. The tree should be removed at night, and set out in the same relative position to the sun as in its former aspect. If these rules are followed, no tree will rarely ever die, unless its most vital parts are too extensively injured.
We all know that a plant stripped of its leaves will soon perish. Among the reasons for this is that the absorption by the roots is insufficient to supply all the materials for its nourishment. Let us look a little more closely into these phenomena of nature. There must be a certain number of stages for all herbal growths. First, the ascending sap dissolves the nutritive deposits of the root and stem, and conveys them to assist in the development of leaves and flowers. Hence it is evident that if the root, bark, or stem be gathered at this season, it will prove deficient in medicinal virtues, or be altogether inert. The leaves also will be found worthless for remedial purposes. On the other hand, if we wait a little longer, or until the plant is fully developed, we will find that either the bark or root, the leaves or flowers, are full of rare medicinal virtues.
The precise moment when all the assimilative processes of the plant have been perfected -- whether it be Summer or Winter, Spring or Autumn -- is the time to gather it for a remedial agent in disease, inasmuch as we know that the laws of chemical decomposition and recombination know no rest; hence, as in the case of the nettle, while it may be a good food in its earlier stages of development, it would prove a poison in a more advanced stage of its growth.
The peculiar properties of herbs as medicines will often depend upon the greenness or ripeness of the plant, and other circumstances attendant upon its cutting, and the length of time it is kept after being gathered.
For instance, the concrete juice of the Manna ash (Fraxinus Ornus) -- the manna of commerce -- increases in purgative qualities by age. The Oak-bark, for tanning hides, improves in value for a period of four or five years after it has been stripped from the trunk; in the same manner, its medicinal properties are either diminished or improve, according to the season when the bark is gathered, or the manner in which it is converted into tannic acid for medical or scientific purposes.
It must be apparent to all, that herbs are liable to suffer from the vicissitudes of soil, climate, season, etc., and, as a mtter of course, from these causes will vary the medicinal principles attributed to them.
Repeated analysis demonstrates the fact, that specimens of the same plant, grown in different localities, will vary infinitely in the proportions of the medicinal principles yielded. Take, for example, the Butterfly-weed or Pleurisy-root (Asclepias Tuberosa), which grows in the barren and sandy soil of New Jersey, and it will be found to yield from one to two hundred per cent of its medicinal virtues more than the same plant grown in the rich alluvial soils of the West. Hence, when given as medicine, the quantity must correspond accordingly -- be either increased or diminished, in order to secure its proper curative effects upon the system. Thus it is seen that a medicine, prepared from plants culled at an improper season, will prove entirely inert or useless, while the same herb, gathered at a proper time in a proper climate, especially and properly prepared, would secure the restoration of a patient from disease to health.
There is likewise a wide difference between the virtues of a plant growing in a wild or natural condition from that of the same herb when artificially cultivated. The transference of plants from their native locations, to soils prepared by the hands of man, induces many changes in their individual elements. Many plants formerly used for medicines are not cultivated for the table alone. The small acid root of the Brassica Rupa has become the large and nutritious article of diet known as the turnip. The dandelion, when grown in natural localities, possesses well-defined medical properties, all of which are lost when the plant is artificially cultivated. In the cultivated plant the proportions of starch, grape-sugar, and other non-medical principles are largely increased while that which is gathered in its wild or native state is known to possess rare virtues in affections of the liver, kidneys, and respiratory organs. In the cultivated rose the stamens are converted into petals. The castor-oil plant in Africa is a woody tree -- in our gardens it is an annual. The mignonette, in Europe, is an annual plant, but becomes perennial in the sandy deserts of Egypt.