Abstract
The theory of spontaneous generation was developed by Aristotle, mainly in his biological works. In Aristotle, this issue was linked with some significant doctrines, such as that of pneuma. In medieval thought, the theory was known as generatio ex putrefactione. Albert the Great addresses it not only to explain the generation of certain animals, such as insects, but also to elucidate the generation of certain plants. Moreover, in Albert the Great’s De vegetabilibus, putrefaction is conceived as a process that simply pertains to the life of plants: putredo is one of the three principles of plant generation, meaning that plants need putrefaction to germinate and grow, even if seeds initially bring them about. In Albert’s explanation, there is only a thin line between spontaneous and conventional generation in plants, so that putrefaction and generation are two symbiotic concepts in the vegetal world.