Lazzaro Spallanzani attempts to prove that abiogenesis,…
1780 CE
Lazzaro Spallanzani attempts to prove that abiogenesis, the study of how biological life could arise from inorganic matter through natural processes, does not work.
Spallanzani had researched in 1768 the theory of the spontaneous generation of microbes.
At the time, the microscope was already available to researchers, and using it, the proponents of the theory, Buffon and Needham, came to the conclusion that there is a life-generating force inherent to certain kinds of inorganic matter that causes living microbes to create themselves if given sufficient time.
Spallanzani's experiment showed that it is not an inherent feature of matter, and that it can be destroyed by an hour of boiling.
As the microbes did not re-appear as long as the material was hermetically sealed, he proposed that microbes move through the air and that they could be killed through boiling.
Needham had argued that experiments destroyed the "vegetative force" that was required for spontaneous generation to occur.
Spallanzani has paved the way for research by Louis Pasteur, who will defeat the theory of spontaneous generation almost a century later.
Spallanzani discovers and describes animal (mammal) reproduction, showing that it requires both semen and an ovum.
He is the first to perform in vitro fertilization, with frogs, and an artificial insemination, using a dog.
Spallanzani shows that some animals, especially newts, can regenerate some parts of their body if injured or surgically removed.
Spallanzani is also credited with the classification of tardigrades ("water bears"), which are one of the most durable extremophiles still to this day.
Spallanzani is also famous for extensive experiments on the navigation in complete darkness by bats, where he concluded that bats use sound and their ears for navigation in total darkness.
He is the pioneer of the original study of echolocation, though his study is limited to what he can observe.
Later scientists will move on to studies of the sensory mechanisms and processing of this information.
His great work, however is the Dissertationi di fisica animale e vegetale (2 vols, 1780).
Here he first interprets the process of digestion, which he proves to be no mere mechanical process of trituration—that is, of grinding up the food—but one of actual chemical solution, taking place primarily in the stomach, by the action of the gastric juice.
He also carries out important researches on fertilization in animals (1780).