Nature is a book about life. The shapes, colors, and growth habits of plants tell stories of the difficulties they have encountered in the course of their development, and the way these have been overcome. Physical stresses caused by shortage or surplus of heat, cold, nutrients, sunlight, shade, wind, and rain, have given exact forms to the plants, individualizing one from another. These precisely articulated shapes and qualities correspond to the medicinal properties vested in the herb, because the qualities within the plant are also an expression of the conditions which formed it.
The same environment which molded the plant also brought the human organism into existence. Each organ of the body, with its different function and internal environment, represents a response to the difficulties presented to it by nature. The organ in its living space is analogous to the plant within its. When the body is stressed beyond its capacity for self-restoration the plant which corresponds to the lost function will "teach" the body how to take up the job again, because it fulfills a corresponding fuction in nature.