Abstract

Although in his study of biological problems Spallanzani tended towards the animal world, on several occasions he exploited the vegetal world to confirm the 'laws' that he discovered (or believed to have discovered) in the animal kingdom. Thus, his work on mould proved useful to 'destroy' the theories postulated by Buffon and Needham as to the origin of protozoa and of 'spermatic worms'. Later Spallanzani turned again to plants to confirm what he believed he had seen in amphibian eggs: as the egg contains, preformed, the embryo under the form of an invisible 'germ', so the seed of the plant contains the 'germ' of the future plant. The observations conducted on some types of plants convinced Spallanzani that he was right: a series of experiments on flowers that had not been pollinated demonstrated that also in this case the 'germ', which is at first invisible, develops into an embryo. Therefore, also in plants the embryo exists prior to fertilization. Recent studies conducted with the aim of testing the apparently anomalous results obtained by Spallanzani have clearly demonstrated that his experiments were technically correct, and that his observations were exact. The plants in which he demonstrated the 'pre-existence' of the germ may in fact present phenomena analogous to parthenogenesis, a state that Spallanzani obviously ignored. The interest of the present article lies essentially in the fact that it is the first study dedicated by a distinguished botanist to Spallanzani's work in the vegetal world: a topic that up to now has been systematically ignored by historians of science, and that requires further study