Open classification: scientists, celebrities, Italians
Lazaro Spalla (1729— 1799) is a famous Italian naturalist, physiologist and experimental physiologist.
biography
Spalla Jie was born in June 65438 +0729 65438+10/October 65438+February in the Italian town of Candiano. His father is a famous lawyer and his mother comes from a rich family. /kloc-After graduating from high school at the age of 0/5, Spalla entered Lezo-Emilia Jesus Theological Seminary, where he studied for five years and received a good education in linguistics and philosophy. 65438-0749 transferred to the famous University of Bologna to study law. His cousin Basi is an outstanding woman and a professor of physics and mathematics at the University of Bologna. Under her guidance, Spalla Jie became interested in natural science, transferred to natural science, and obtained his doctorate at 1753. Shortly thereafter, the church appointed him as a priest and became a priest on 1760. The financial support of the church ensured the smooth progress of his scientific career.
176 1 year, the first scientific expedition. By studying many interrelated factors, he proved that the spring water in the mountain did not come from seawater as Descartes said, but came out after rain (snow) water infiltrated into the ground as Varis Neri pointed out. This fully demonstrates Spalla Jie's rigorous attitude and logical thinking ability. This year, Varis Neri introduced Buffon and Needham's thoughts and works on natural occurrence to him, which aroused his great concern. Since 1762, he has conducted in-depth research on natural problems and achieved great success.
Spontaneous generation theory is an ancient hypothesis about the origin of living things, which holds that living things are developed from abiotic substances. From the earliest days of human civilization to the17th century, the theory of spontaneous occurrence is almost universal and unquestionable in people's minds. Aristotle is the representative of the theory of spontaneous occurrence. He believes that the combination of morning dew with mucus or feces will produce larvae of fireflies, worms, bees and so on. Hellmont even proposed a method to produce mice. 1668 Italian doctors enthusiastically proved that maggots born from carrion were hatched from eggs laid by flies, thus refuting the above absurd understanding. Through hundreds of comparative experiments, Spalla Jie found that if the immersion liquid is boiled in a sealed flask for 1 hour, there will be no more microorganisms. He pointed out that the microorganisms in the immersion liquid were caused by incomplete disinfection or air pollution. Spalla Jie's research on the problem of natural occurrence is of double significance: first, he refuted the theory of microbial natural occurrence with scientific experiments nearly a century earlier than Pasteur, and his experimental conception was quite ingenious, which was highly praised by Pasteur. He specially asked someone to draw a portrait of Spalla Jie and hang it in a restaurant for daily viewing. Therefore, he invented the high temperature disinfection method. This is how the first can of canned food was made. Of course, due to the limitation of historical conditions, he failed to completely refute the theory of spontaneous generation of microorganisms, nor did he answer the question of the original origin of life. 1765, Spalla Jie published his paper "Observing Experiments with a Microscope", summarizing his research on naturally occurring problems. Swiss naturalist C.Bonnet was very happy after reading this paper, and began to establish friendship with Spalla Jie, and soon became good friends.
1765, Spalla Jie began to study the regeneration ability of animals. He has done thousands of experiments with earthworms and realized the exact location of some incisions that are conducive to earthworm regeneration. After studying the tentacles of slugs, the head, tentacles and feet of snails, the tail, limbs and maxilla of salamanders, and the limbs of frogs and toads, he found that animals have stronger regeneration ability than higher animals, larvae are stronger than adults, and body surface tissues are stronger than internal organs. In addition, he also made a successful allogeneic head transplantation experiment with snails. He collected his research results in two books, namely Animal Regeneration and Experimental Results of Head Regeneration of Land Snails.
During this period, Spalla Jie also made a systematic study on the blood circulation system of animals. With regard to blood circulation, Harvey made a basic research on blood circulation. Spalla Jay observed that the heart beat rhythmically, thus promoting blood flow. He found that the blood in the aorta also had a rhythmic beating flow and began to become uniform when it reached the arteriole. He also observed that individual red blood cells sometimes deform to pass through curled capillaries. He also discovered for the first time that in warm-blooded animals, there is a structure in which arteries and veins are intertwined. It is pointed out that besides the pressure produced by the heart, the beating of the artery also has the elastic effect of the blood vessel wall. 1768 published the article "the movement of the mind" and summarized the achievements in this respect. In the same year, Spalla Jay was elected as a member of the Royal Society of London.
From 65438 to 0777, Spalla Jay began to study the digestive physiology of animals. At that time, it was generally believed that the animal's stomach could only grind food, but could not decompose the organic matter in food, that is, the animal's stomach only digested physically, not chemically.
1783, Spalla Jie put food in a metal tube or small ball with small holes, and let animals swallow the small ball with meat pieces, so that the food is not affected by physical digestion, but the liquid in the stomach can enter the small ball. After a while, he took out the ball and found that the meat in the ball was gone, so he decided that there must be something in the liquid in his stomach to digest food. He first introduced the word "digestive juice", thinking that digestive juice contains some chemical components that can decompose food. The so-called digestion is the decomposition process of food by digestive juice. This is essentially different from corruption. He pointed out that digestive juice has a strong bactericidal effect. He used experiments to prove that the digestion speed is not only related to the nature of food and the amount of digestive juice, but also related to temperature, and body temperature is the most suitable temperature. He also pointed out that the secretion of small intestine may complete the whole digestive process. Due to the backward experimental conditions and methods at that time, Spalla Jie didn't find out what substances in gastric juice digested food. It was not until more than 50 years later, that is, 1836, that the German physiologist Wang Shi extracted protein-digesting substance from gastric juice, which was later called "pepsin", thus solving the mystery of gastric digestion.
In1771-1780, Spalla Jie also conducted research on fertilization. Now we know that the offspring of sexually reproductive organisms produce fertilized eggs through the combination of sperm and egg cells, that is, fertilization, and then develop from fertilized eggs. However, in the18th century, the understanding of fertilization process was still quite vague. 1677, people discovered sperm, and eggs have long been known, but what is the relationship between them in the process of fertilization?
One view is that sperm plays an important role in fertilization, but ignores the role of egg cells. 1677 In August, J Hamm observed sperm for the first time, which was recognized by Levin Hook. Later, some scholars think that there are very small people in human sperm and very small animals in other animals' sperm, which is the view of sperm source theorists. The other is the view of oogonists, who despise the role of sperm. Buffon and others believe that sperm is just a parasite in semen. Even if some scholars admit that semen works, it was not clear at that time which part of semen works. Spalla Jie is an egg source theorist. He believes that an egg contains a tiny individual of an organism, such as a frog, which already exists in the egg. Thus, tadpoles already exist in the eggs before they are excreted-they curl up in some way and gather closely together, and they are ready to expand themselves as long as there is a male liquid that can fertilize them.
Although some of Spalla Jie's viewpoints are incorrect, he has made great achievements in the research of fertilization. He designed many wonderful experiments and denied some wrong ideas. When observing the reproduction of amphibians such as frogs and salamanders, he found that they were fertilized in vitro, thus denying the wrong view that animals can only be fertilized in vivo but not in vitro. Specifically, he designed a special kind of taffeta trousers for male frogs. Frogs in these unique clothes try to mate as usual. After mating, although the female frog laid a lot of eggs, they could not develop. Normal development begins when some eggs come into contact with semen left on pants. Later, he collected semen directly from seminal vesicle and carefully "smeared" it on the egg. These treated eggs can develop into tadpoles normally, while eggs that have not been exposed to semen will disintegrate. In this way, Spalla Jie invented an artificial insemination method.
Spalla Jie also used artificial insemination to further explore which parts of semen have fertilization function, and whether non-semen substances have fertilization function. He also designed a series of ingenious experiments. He used blood, blood paste, electric current, vinegar, wine, urine, lemon juice, oil and other substances to contact with frog eggs, and as a result, frog eggs could not be fertilized and developed. Even if the frog semen is diluted to the original concentration of 1/8000, it still has fertilization ability. So which component in semen has fertilization ability? Some people say it's the smell. In order to verify this view, he first dropped a few drops of frog semen on a piece of glass, then stuck gluten on another glass cover, and 26 frog eggs were stuck on the gluten, and then turned the glass cover on the semen upside down so that sperm and egg cells did not contact. After a period of time, the semen in the device evaporated by half. At this time, the egg was wet, but after the egg was put into water, it did not develop. In order to check whether the remaining semen is effective, he contacted some eggs with these semen, and these eggs fertilized and developed. Through this experiment, Spalla Jay proved that the smell of semen can't fertilize eggs. Later, he filtered the semen and divided it into two parts, mucus without sperm and mucus with sperm, and then used it in artificial insemination experiments. It was found that the former had no fertilization ability, while the latter still had fertilization ability after being diluted with water. The fact is obvious, but because of Spalla Jie's original knowledge and belief, he thinks that it is the liquid left on the filter paper, not the sperm, that completes fertilization.
In addition, Spalla Jay also studied the discharge phenomenon of electric eels and the orientation of bats when flying. At the same time, he was a tireless traveler and fearless explorer, and he made pavia Natural Museum the most famous Italian museum. He is also one of the founders of volcanology.
Spalla Jie suffers from prostatic hypertrophy and chronic cystitis, which eventually leads to anuria. 1February 799 1 1 passed away at the age of 70. Spalla Jie devoted his whole life, together with a part of his body, to the cause of science. According to his will, his sick bladder was presented to the pavia Museum of Natural History.
Spalla Jay's Bat Experiment
1793 One night in the summer, Italian scientist Spalla went out and put some bats in cages to do experiments. I saw that the bat fluttered its limbs with film and flew lightly into the night sky, making a free "squeak" cry ... Spalla Jie was puzzled after seeing it, because before he released the bat, he had blinded the bat's eyes with a small needle. "How can a blind bat fly so fast?" He made up his mind to solve the mystery.
Before this experiment, Spalla Jay always thought that bats could fly freely in the night sky and avoid various obstacles to catch flying insects in very dark conditions. It must be because of a pair of very keen eyes. The reason why he wants to blind bats is to prove it. The fact was completely out of his expectation.
This unexpected situation aroused his curiosity even more. "Without eyes, how can bats identify obstacles and catch food?" So he blocked the bat's nose again and let it out. As a result, the bat flew easily. "Will the mystery be on the wings?" Spalla Jay painted a layer of paint on the bat's wings this time. However, this did not affect their flight at all.
Finally, Spalleger plugged the bat's ears again ... This time, the bats flying in the sky bumped into each other and fell down quickly. Spalla Jay realized that bats rely on hearing to determine direction and catch targets.
Spalleger's new discovery caused people's shock. Since then, many scientists have further studied this subject. Finally, people finally figured out that bats use "ultrasound" to navigate at night. The high-frequency sound waves emitted by its throat are inaudible to human ears. This sound wave travels in a straight line and returns as soon as it touches an object. They use their ears to receive the returned ultrasonic waves, so as to make accurate judgments and guide them to fly.
The scientific principle of "ultrasound" has been widely used in navigation, navigation and medicine. 1793 In the summer, Spalla Jie came to an old house in the suburbs on a hot afternoon and caught some bats. He put them in the cage and went home happily. He thought: Today, I must find out, what do bats rely on to make them fly freely at night?
In the evening, after he finished his dinner in a hurry, he took out the pigments prepared in advance and drew a bat's body. 1, 2, 3, 4 finally helped these elves put on their "black coats". So it released all the painted bats. As a result, bats are still flying so quickly and easily in the night sky, and coloring them has no effect on their flight at all. Spalleger doesn't understand. He scratched his head and felt a little discouraged, but he didn't give up an opportunity because he believed he would succeed.
Spalla Jay watched these little things flying freely in the sky and decided to go outside to catch bats for experiments tomorrow. We must find out what special skills bats rely on to fly freely in the sky. Yes