Lazzaro Spallanzani (
1729-
1799) was an important
Italian physiologist who made countless contributions to the study of anatomical and reproductive functions and animal and microscopic life. His most important experiments dealt with how
sexual reproduction actually occurred. Sure, we knew about the
sperm and the
egg, but we didn't figure out until remarkably late in human history how all the parts fit together (no pun intended). And it took a
celibate Catholic priest to do it.
Born in
Modena, he was the son of a
lawyer. He studied the classics,
philosophy,
mathematics, and languages at the
Jesuit school in
Reggio. Though he eventually took
holy orders in
1757 and worked as a
priest, he never joined the Jesuit order. Instead he went to
Bologna to study law, but his interests soon turned towards
science. He also held various teaching posts, becoming professor of
logic,
metaphysics, and
Greek at
Reggio College in
1754 and professor of
physics at the
University of Modena in
1760.
Through all this, plus penning the occasional work of
literary criticism, all of
Spallanzani's spare energy was directed towards his scientific experiments. In
1766, he published a work examining the physics of how stones bounce when thrown across a body of water. In
1767, he first turned to
biology, writing an attack on the theory of "
vital atoms", theoretical particles which were the source of physiological activity. He, like
Antonie van Leeuwenhoek, though these "vital atoms" were
microorganisms, which they of course were, which he proved through a series of experiments with boiling gravy, showing that the leftover particles were microorganisms introduced through the air and not part of the original substance.
1768 produced the results of his experiments in animal
regeneration and
transplantation, one of which was a successful transplant of the head of one
snail onto the body of another one. In
1773, he studied
blood circulation in the
lungs and organs and the chemicals in
digestive juice.
But you want to hear about
sex, right? The sperm and the egg were discovered in the 17th century, and it was assumed that both played a role, but no one quite stumbled on the obvious yet. By the next century, the prevailing theory was "remote
fertilization": the sperm and the egg merely needed to be in the same neighborhood and the egg would be exposed to the invisible
aura seminalis ("spermatic vapor"). Presumably
ether or
phlogiston were not acceptable substitutes.
Spallanzani believed this nonsense, but his experiments separating
toad eggs and
semen proved that physical contact was necessary between the egg and the sperm. He gathered a quantity of
frog sperm by clothing male frogs in makeshift
taffeta "pants" (dear
God, could I make this stuff up?) and setting them loose on female frogs. When the males mounted the females, they ejaculated into the pants, allowing Spallanzani to collect it for his research. He then placed the sperm and the eggs into separate containers, where the "vapor" could reach the eggs but there was no physical contact. No dice. But when he mixed the eggs and the
seminal fluid, instant
tadpole soup.
And thus some of the first experiments in
artificial insemination. But he wasn't finished there. Frogs were one thing,
mammals another. So he isolated a male and a female dog from one another, masturbated the dog to collect the sperm, and inseminated the bitch with it. Soon he had plenty of puppies to give away.
Despite his successes, he could never manage to crossbreed
cats and dogs.
Through these strange experiments, Spallanzani became famous in scientific circles. He was offered a chair at the
University of Pavia in
1769, which is where he would stay for the rest of his life. His popularity brought jealous accusations of
malpractice, which he emerged from unscathed. Later experiments involved the
electrically charged
torpedo fish, the senses of the
bat, and the conversion of
oxygen to
carbon dioxide in the body. He also traveled extensively, penning accounts of his trips to
Constantinople and
Sicily.