Trembley discovered the hydra and was the first to observe in it asexual reproduction, regeneration, and photosensitivity in an animal without eyes. His experiments were of great importance in the study of regeneration of lost parts. He was the first to make permanent grafts and to witness cell-division. A biography of Trembley was published by J. R. Baker, London, 1952. English translation in S.G. and H.M. Lenhoff, Hydra and the birth of experimental biology, Pacific Grove, CA, 1986. Digital facsimile of the 1744 edition from the Biodiversity Heritage Library, Internet Archive, at this link.