Jean-Joseph Virey (1775-1846) was a French physician and naturalist to whom we owe a systematic study of the relation between the color of a medicine and its action, the color of flowers and other parts of the plant as a distinguishing property, and the odors of different substances. The colors of vegetables indicated, in general, their dominant principles and could serve to establish the difference in medical matter. The odors of different natural substances, and particularly those of medicines, constituted an essential part of their properties. Odors acted upon the different systems of a body and operated on humans like medicines. Virey believed that the aphrodisiac dudaim of the Bible were an orchid, probably one of those from which the salep was prepared. Plants were able to experience impressions of excitability from light, heat, dry or humid air, electricity, and other surrounding agents. Vegetable and animal poisons usually operated on living organisms and according to the organization mode of the species upon which they acted; they could became food, medicine, or poison to the entities that absorbed them. The production of a gall was a clear manifestation of the irritability of the tissue of vegetables, analogous to the bite of the insect, which deposited an acrid and stimulating poison on the wound of an animal. Virey speculated on the effect of cold on organized organisms in general and on the wonderful art that nature appropriated these beings to the coldness of the poles or to the equatorial ardor, to assure their subsistence
