The organization of the Museum is the same now as in 1793, having for over a century been the chief biological centre of France, and with its magnificent collections was never more useful in the advancement of science than at this moment. Let us now look at the composition of the assembly of professors, which formed the Board of Administration of the Museum at the time of his appointment. The associates of Lamarck and Geoffroy St. Hilaire, who had already been connected with the Royal Garden and Cabinet, were Daubenton, Thouin, Desfontaines, Portal, and Mertrude. The Nestor of the faculty was Daubenton, who was born in 1716. He was the collaborator of Buffon in the first part of his _Histoire Naturelle_, and the author of treatises on the mammals and of papers on the bats and other mammals, also on reptiles, together with embryological and anatomical essays. Thouin, the professor of horticulture, was the veteran gardener and architect of the Jardin des Plantes, and withal a most useful man. He was affable, modest, genial, greatly beloved by his students, a man of high character, and possessing much executive ability. A street near the Jardin was named after him. He was succeeded by Bosc. Desfontaines had the chair of botany, but his attainments as a botanist were mediocre, and his lectures were said to have been tame and uninteresting. Portal taught human anatomy, while Mertrude lectured on vertebrate anatomy; his chair was filled by Cuvier in 1795. Of this group Lamarck was _facile princeps_, as he combined great sagacity and experience as a systematist with rare intellectual and philosophic traits. For this reason his fame has perhaps outlasted that of his young contemporary, Geoffroy St. Hilaire. The necessities of the Museum led to the division of the chair of zoölogy, botany being taught by Desfontaines. And now began a new era in the life of Lamarck. After twenty-five years spent in botanical research he was compelled, as there seemed nothing else for him to undertake, to assume charge of the collection of invertebrate animals, and to him was assigned that enormous, chaotic mass of forms then known as molluscs, insects, worms, and microscopic animals. Had he continued to teach botany, we might never have had the Lamarck of biology and biological philosophy. But turned adrift in a world almost unexplored, he faced the task with his old-time bravery and dogged persistence, and at once showed the skill of a master mind in systematic work. The two new professorships in zoölogy were filled, one by Lamarck, previously known as a botanist, and the other by the young Étienne Geoffroy St. Hilaire, then twenty-two years old, who was at that time a student of Haüy, and in charge of the minerals, besides teaching mineralogy with especial reference to crystallography.