A hundred years after the discovery of Camerarius a book appeared that cast a new and living light on the question of the sexuality of plants. Like the elder one, it also was not appreciated by the students of the time. Although Camerarius had shown, between 1691 and 1698, the necessity of the intervention of the pollen in the act of the fecundation of plants or the production of the seed—or, to use one of Goethe's expressions, that plants gave themselves up, in the bosom of the flower, to the sports of love—the special destination of the different parts of the plant remained a riddle.
But flowers, with their special properties, the richness of their living colors derived visibly from the green of the leaves, the wonderful variety of their forms, and the perfumes with which they made the air fragrant, continued to attract the attention of the learned world. In 1793 a schoolmaster, the regent Christian Conrad Sprengel, of Spandau, again withdrew the veil, and showed with rare penetration, confining himself to the genus, what were the functions of the organs of the flower, and chiefly of the colored petals. The facts he disclosed, and which are now part of the incontestable patrimony of science, appeared so surprising to him that he entitled his book The Mystery of Nature unveiled in the Structure and Fecundation of Plants. He also advised the botanists of his time to study plants in vivo, in Nature, instead of contenting themselves with the examination in their studies of dried and withered specimens in a herbarium. His discovery was of so great importance to the scientific explanation of the functions of the different floral organs that it is hard to explain how his book, still remarkable and interesting, could have passed unnoticed. Incredible as it may appear, it is nevertheless true that his ingenious work remained unknown till 1862, when Charles Darwin, being occupied with the same question, found it and made it known.—Translated for The Popular Science Monthly from the Revue Scientifique.