Lazaro Spallanzani

Life and discoveries of Lazaro Spallanzani

1. Lazzaro Spallanzani Team 1 & Team 2 (Spain): Clara, Diana, Mario y Paula.

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. Spontaneous Generation “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 V egetative F orce “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. Air Elasticity → The Last Experiment 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 and bats

18. Videos 2 min Spontaneous Generation 13 min

19. Bibliography “Microbe Hunters” by Paul de Kruif http://scienceworld.wolfram.com/biography/Spallanzani.html http://www.whonamedit.com/doctor.cfm/2234.html https://embryo.asu.edu/pages/lazzaro-spallanzani-1729-1799 http://www.encyclopedia.com/topic/Lazzaro_Spallanzani.aspx http://www.infoplease.com/cig/biology/spontaneous-generation.html http://www.genesis-ultrasound.com/Lazzaro-Spallanzani.html https://www.youtube.com/watch?v=xtyBzNQekjY