Galvani biography

The biography was born on September 9 in Bologna. At first he studied theology, and then medicine, physiology and anatomy. He graduated from Bologna University with a degree in theology, and only after defending the dissertation did he become interested in medicine under the influence of his father -in -law - a famous doctor and professor of medicine Carlo Galeazzi.

Despite the academic degree, Galvani abruptly changed his profession and graduated from Bologna University, but already a medical department. Galvani's master's work was devoted to the structure of human bones. After her successful protection in Galvani, he began to teach medicine. In the year, after the death of his father -in -law, Galvani took his place of the head of the Department of Anatomy and Gynecology, from where he was fired shortly before his death for the oath of the Tsizalpin Republic, founded in the year, Napoleon I.

The first works of Galvani were dedicated to comparative anatomy. He began experiments on the study of muscle contraction and soon discovered the phenomenon of contraction of the muscles of the prepared frog under the influence of electric current. By the end of the 18th century, scientific activity John Walsh proved the electrical nature of the stroke of the slope, conducting experiments in the French city of La Rochelle, and Anatu Hunter gave an accurate description of the electric organ of this animal.

Studies of Walsha and Hunter were published in the year. By the time Galvani laid the foundation for his experiences in the year, there was no shortage of attempts to physical interpretation of mental and physiological phenomena. However, it was the studies of the above scientists that prepared the ground for the emergence of the doctrine of animal electricity.

In the year, in the Treatise on the forces of electricity during muscle movement, the famous discovery made by Galvani was described. The phenomena themselves, open galvanas, for a long time in textbooks and scientific articles were called "galvanism." This term is still preserved in the name of some devices and processes. Galvani himself describes his discovery as follows: as Volta rightly indicated, in the very fact of trembling the paw of the preparationed frog with an electric discharge from a physical point of view, there was nothing new.

The phenomenon of electrical induction, namely the phenomenon of the so -called return strike, was dismantled by Magon in the year. However, Galvani approached the fact not as a physicist, but as a physiologist. The scientist was interested in the ability of a dead drug to show life contractions under the influence of electricity. He studied this ability with the greatest patience and art, studying its localization in the drug, the conditions of excitability, the effect of various forms of electricity and, in particular, atmospheric electricity.

Galvani's classical experiments made him the father of electrophysiology. Galvani, having carried out a number of experiments, came to the conclusion about the existence of a new source and a new type of electricity. He was led to this conclusion by the experiments of compiling a closed chain from conducting bodies and metals best, according to the recognition of the scientist himself, it was used to use different metals, such as an iron key and a silver coin and frog drug.

After long scientific research, Galvani suggested that the muscle is a kind of battery of Leiden cans, continuously excited by the effect of the brain, which is transmitted through the nerves. That is how the theory of animal electricity was born, it was this theory that created the base for the emergence of electromedicine, and the opening of the galvania made a sensation.

Among the followers of the Bologna Anatom was Alessandro Volta. Luigi Galvani was born in Bologna on September 9. Outwardly, his life was unremarkable. In the city, he was engaged in medicine and anatomy. His dissertation was devoted to the structure of bones; In addition, he studied the structure of the kidneys and ear of birds. Galvani received a number of new data but he did not have to publish them, since a little earlier most of these facts were described by Italian scientists A.

This first scientific failure did not discourage Galvani. He was a wonderful lecturer, and his lectures enjoyed great success among students. He worked a lot as a surgeon. Medical practice and teaching work took a lot of time, but Galvani, as the true son of his era, did not throw purely scientific work: both descriptive and especially experimental, with G. Galvani began work on the physiology of nerves and muscles, which brought him worldwide glory and many troubles.

So, it is clear why Galvani doctor was experimenting and why he had a frog drug on his table. But where does the electric Luigi Galvani is the machine? At this time, electricity was considered as an “electric fluid” as a special electric fluid. This hypothesis arose after Gray discovered that electricity could “flow” from one body to another if they are connected by metal wire or other conductors.

This hypothesis, of course, was inspired by the ideas that then dominated in other sections of physics. The properties of weightless fluid - ether - explained the wave spread of light; Heat was also considered a weightless liquid.The hypothesis of the essence of electricity was subjected to experimental verification. The electrified bodies were carefully weighed and could not find weight gain.

Thus, the idea of ​​the weightlessness of the electric charge was the result of not only speculative reasoning, but also a consequence of insufficient accuracy of measurements. When it turned out that the electric charge could not be measured with weighing, physicists began to invent fundamentally new devices. One of the first electrometers was designed by Rihman. At first it was believed that electric fluid is one of the varieties of the “heat”, this circumstance was justified by the fact that during friction of the body they are heated and electrified, as well as the fact that an electric spark could light various objects.

Finally, it was shown that electricity conductors carry out heat well, and insulators are bad. However, in the end, an idea was established that an electric weightless fluid differs from the heat. Firstly, it was shown that the bodies that are electrified by touch do not heat up. Secondly, Gray showed that continuous and hollow bodies are electrified in exactly the same way, and heats up differently, and concluded that the “heating” spreads throughout the volume of the body, and the electric fluid spreads over the surface.

Thus, the idea of ​​electricity as a weightless fluid was experimentally substantiated at the level of the capabilities of physics of the XVIII century and fit well into the general ideology of physics of that time. We have already said that at this time a variety of phenomena - even earthquakes - tried to explain with electricity, the “nervous mechanism” was no exception. In g, the French doctor Dufei defended the dissertation on the topic “Is the nervous fluid with electricity?

The idea was supported by the same idea in G. clearly in the air. In connection with these ideas, two areas of experimental research - the study of electricity and the study of processes in nerves and muscles - came into contact with each other. There was a hope to establish that the processes in the nerves are the processes of electrical nature. In addition, electric discharges were widely used at this time for irritation of nerves, skeletal muscles or hearts of the Leiden jar for this purpose used, for example, D.

Bernoulli and the same F. Fountan, which we already talked about. Now we should not seem strange and random to us that on the table of the doctor Galvani, who was a student of the fountain and was engaged in experimental study of the work of muscles and nerves, was an electric machine. The point is not that he paid tribute to fashion. The car was needed because he, as they would say now, worked not just at the front edge of science, but at the junction of two sciences: physiology and science about electricity.

After all that was said, another becomes incomprehensible: which attracted the attention of the assistant to Galvani, why the contraction of the muscle during electric discharge seemed so wonderful. After all, the fact that electricity acts as an irritant on nerves and muscles was a widely known fact. The fact is that before the observations of Galvani, this irritating effect was observed only with the direct contact of the charged body with the muscle or nerve.

There was no such contact here. Faced with a new unfamiliar phenomenon, Galvani, as the true son of his century, begins to carefully and comprehensively investigate this phenomenon. He puts a wide variety of experiments. For example, it shows that the effect is also observed when the frog's paw is placed under the pump bell into an airless space, when a Leiden Bank is discharged instead of an electric machine.

And even when the frog foot is included in the chain between the thunderbone and the ground, it is reduced at the moment when lightning skipped. But no matter how interesting these experiments were, they did not give any fundamentally new information about electrical phenomena in living organisms: another form of the irritating effect of electricity was discovered, but physicists knew that the bodies could be electricized without touching, at a distance.

Galvani begins a new series of experiments, deciding to study the effect on the muscles of the frog of "calm" atmospheric electricity. By this time, it was shown that electricity is in the atmosphere and in the absence of a thunderstorm. Realizing that the frog's foot is in a sense a very sensitive electrometer, he decided to try to find atmospheric electricity with its help.

Having hung the drug on the grill of his balcony, Galvani had been waiting for the results for a long time, but the foot did not contract in any weather. And on September 26, this did not happen when the weather changed, but under completely different circumstances: the frog's foot was suspended to the iron grate with a copper hook and a hanging end accidentally touched the lattice, Galvani checks: whenever the “iron - copper -paw” chain is formed, the paw muscles are immediately reduced, regardless of the weather.

Galvani transfers experiments to the room, uses different pairs of metals and regularly observes the contraction of the muscles of the frog foot.This is something completely new, no sources of electricity nearby there is no car or thunderstorm, and the foot of the frog is reduced. Galvani puts a beautiful experience in the spirit of his time, when spectacular public demonstrations were very popular.

The foot is suspended on a copper hook connected to a silver box, standing so that the lower part of the foot touches the box. The foot is reduced and pulled away from the casket, the chain opens from this, then the foot lowers again, touches the casket again, rises again, etc., as Galvani says, something like an electric pendulum. In fact, this system is completely similar to the current interruption in an electric call, but there was no current or a call at that time.

How to explain these observations? Since the time of Gilbert, it was known that the metal could not be electrified by friction. Galvani, like other scientists of his time, believed that electricity could not occur in metals, they could only play the role of conductors. From here, Galvani concludes that the source of electricity in these experiments is the frog fabrics themselves, and metals only close the chain.

But why do this chain need two different metal? Galvani explores this issue and discovers that you can do and just a piece of copper wire, when using one metal, the reduction does not always arise, it is weaker, but this is already a small detail. Muscle contraction is visually observed, the strength of the contraction is not measured. It is important that two metal are not binding, and therefore insignificant, ”Galvani argues.

Galvani worked with the neuromuscular drug: the posterior paw of the frog with a paped nerve and a preserved piece of spinal cord. In the first successful experience, when the foot hung on the balcony, the copper hook was passed through a piece of the spine, and the tip of the paw touched the iron lattice, Galvani decides that this is the best conditions, and does not try others.