Lazzaro Spallanzani: At the roots of modern biology

The scientific work of Lazzaro Spallanzani is outlined, with emphasis on the elements of originality in his introduction of the experimental method in biology. Particular stress is placed on Spallanzani's contribution to solving the Theoria Generationis, from the problems connected with the spontaneous generation of living creatures to those of natural fertilization and artificial insemination and, finally, those of regeneration. J. Exp. Zool. (Mol. Dev. Evol.) 285:178-196, 1999.