2. Biography
Spallanzani was born in Scandiano (Italy), in 1729. He
was a very famous biologist.
When he was a child,his father wanted him to be a
lawyer, but he grew up to be a well-respected math and
physics teacher at several italian universities.
When he was 15 years old,
he started to study at “Colegio de
los Jesuitas de Reggio Emilia”
where he did courses of
philosophy and rhetoric.
Later, he also joined some scientific societies, such as
the Royal Society.
3. Biography
When he was older, he traveled a lot around the world.
He visited:
Asia (between 1785-1787)
Campania , Sicily, Stromboli , Lipari and the Aeolian islands (autumn)
To collect material for the Museum of Natural History of Pavia , who at that
time was singularly poor in volcanic rocks and minerals
4. Biography
And after seventy years, he died in Pavia in 1799 because of a bladder cancer.
His death was a very big loss for this world because he was a very big scientist
who helped a lot to the investigations of the life provenience.
5. Historical context
Lazzaro Spallanzani (1729-1799) lived in the troubled period of time
when the Illustration and the French Revolution were in the making. It
was a time of great thinking and development, with the Industrial
Revolution.
In Spain, Philip the 5th was trying to get back the territories in the
mediterranean taken by England previously, fighting with all his
strength. There wasn’t much of a revolutionary spirit.
Later, at the time of Spallanzani’s death, Charles the
4th yielded to France, the Directory and Napoleon,
and fought against England. The Spanish monarchy
would fall apart later, with the War of Independence
against the French.
6. Scientifical biography
Founder of experimental biology
He rejected the spontaneous generation theory
theorized by Needham.
He was called the "Biologist of biologists"
Person of multiple scientific interests (the
origin of life, the spontaneous generation,
the breathing and other functions of human
beings, the echolocation of bats)
7. Several investigations
He investigated the ability of many lower
animals to regenerate body parts
He studied the circulation of blood through
the lungs
He experimented with digestive juices
He tried to find out what part of semen was
essential for fertilization
He achieved the artificial insemination of a
dog and several lower animals by their
meticulous experiments
8. S p o n t a n e o u s
“Spallanzani had violent notions about whether life could rise
spontaneously; for him it was on the face of things absurd to
think that animals—even the wee beasts of Leeuwenhoek—could
arise in a haphazard way from any old thing or out of any dirty
mess. There must be law and order to their birth, there must be a
rime and reason! But how to prove it?”
→ Microbe Hunters, Paul de Kruif
9. Redi‘s Experiment
Redi, a famous scientist,
proved that maggots don't
arise from nothing in rotten
meat (as many farmers
thought).
He covered a flask and showed
that, although there were
maggots in the unsealed flask,
the one covered with a thin
cloth was deserted.
10. Needham’s Rebuttal
Needham thought Redi
was wrong.
He covered a flask with
a cork and heated it up,
reasoning that he
would’ve killed all the
microbes like that. He
waited, and when he
observed the flask:
microbes were there.
11. Spallanzani supports Redi
Spallanzani repeated Needham’s experiment,
only he sealed the flask by melting glass instead
of corks and boiled the water for almost an hour.
When he studied the sealed flask: there were no
microbes in it. He then discovered:
- Microbes move through the air
- Microbes can survive the heat of boiling
water for almost an hour.
- Spontaneous generation doesn’t exist
12. The Vegetative Force
“Spallanzani stormed and laughed and was sarcastic and bitter about this
marvelous hoax, this mysterious Vegetative Force. It was the Force, prattled
Needham, that had made Eve grow out of Adam's rib. It was the Force, once
more, that gave rise to the remarkable worm-tree of China, which is a worm
in winter, and then marvelous to say is turned by the Vegetative Force into a
tree in summer! And much more of such preposterous stuff, until Spallanzani
saw the whole science of living things in danger of being upset, by this
alleged Vegetative Force with which, next thing people knew, Needham
would be turning cows into men and fleas into elephants.”
→ Microbe Hunters, Paul de Kruif
13. Spallanani discredits Needham
Needham claimed that
Spallanzani’s experiment had
worked because heating the
seeds had “weakened” the
Vegetative Force.
So Spallanzani heated up
seeds for hours and only
plugged them with corks and
yet...alas, microbes were
there!
The Vegetative Force
doesn’t exist
14. AirElasticity→TheLastExperiment
Needham then said that Spallanzani made the
air less elastic, and it damaged the Vegetative
Force.
Spallanzani made sure that the air elasticity was
the same in and outside the flask, sealed it
carefully, and still the experiment proved him
right one last time→ The Vegetative Force
wasn’t real.
“I was right!”
15. Summary
1 → Spallanzani reads Redi’s books and agrees that spontaneous
generation can’t be possible.
2 → Needham performs an experiment to prove it is real, and
shares his findings.
3 → Spallanzani proves him wrong: seals the bottles with
molten glass and heats it up for a longer time period.
4 → Needham tries to explain his failure with “The Vegetative
Force”.
5 → In two occasions, Spallanzani proves that it doesn’t
exist.
16. Spallanzani’s impact and legacy
He discovered that:
Digestion is a chemical process and not just the
grinding of food.
He was first to do an artificial insemination of a dog.
He also contributed in the discovery of the
reproduction of microbes by binary fission,
successfully isolating one microbe.
Microbes can move through the air and can be
killed by boiling. Louis Pasteur → got
many of his ideas from Spallanzani.
17. He concluded that the primary
mode of navigation of bats was
hearing. They must emit
ultrasound waves that are
inaudible to humans and listen
to the echos to determine
distance and direction of
objects. This idea was received by his
fellow scientists with
ridicule and skepticism.
Spallanzani andbats
