 In embryology, he was a preformationist, but also proposed that organisms are the outcome of a combination of an infinite number of possible microstructures and of their powers.In the life sciences and paleontology, he revealed an amazing transformist intuition, fueled by his study of comparative anatomy and fossils.One of his principal works on this subject, "Protogaea", unpublished in his lifetime, has recently been published in English for the first time.