There is a monument to the unknown dog in St. Petersburg near the Institute of Experimental Medicine, where Pavlov headed the physiology laboratory for many years. It was commissioned and partially designed by the physiologist himself to honor the animals, which died for the sake of scientific progress.

Vladimir Kremlev for RT. Click to enlarge

Pavlov’s dogs are probably as famous as Pavlov himself. Interestingly, his Nobel Award had little to do with conditioning experiments. For about 20 years starting from 1879 he studied how digestion works, revolutionizing our understanding of the process and the role of nervous system in nutrition. He discovered how different ferments and acids act on various stages of digestion to transform food into simpler components absorbed by the organism. This work, rather than experiments with bells and feeding, won him the world’s most prestigious award in medicine in 1904.

In the 1900s, Pavlov’s research switched to the central nervous system and conditioning. While working with dogs, he noticed that they started to produce saliva when hearing the footsteps of the lab technician who usually fed them, even though no actual food was present. Pavlov reasoned that the two stimuli became associated and that a similar mechanism was behind the learning process in both animals and humans.

The numerous experiments on linking different stimuli together and their interaction contributed to the birth of modern behavioral science. The laboratory where Pavlov did them was dubbed the “Tower of silence” because its walls were soundproof so that no noise from the street could affect the dogs.

Pavlov’s other area of research at the time was reactions to overwhelmingly shocking experiences, which eventually cause the shutdown of an organism. Later he was involved in psychiatry and studied neuroses.

Apart from research Pavlov was famous as a lecturer and teacher. A plethora of his students became prominent doctors and scientists, and he is credited for creating a whole new Russian school of physiology. An international congress held in Moscow and Leningrad in 1935 titled him “princeps physiologorum mundi” – chief physiologist of the world.

There is much controversy about Pavlov’s religious beliefs. His father was an Orthodox priest and mother came from a priest’s family. He started his education in a seminary, and could have joined the clergy himself if he hadn’t gotten interested in natural sciences. After the Bolshevik Revolution, Pavlov was an outspoken critic of the crackdown on the church. He supported priests with money and on many occasions pulled his weight in society to keep church buildings in the patriarchy’s possession.

While these episodes had been hushed up in the Soviet Union, after its collapse some biographers cited them to prove that Pavlov was a deeply religious man. This was not true. Both Pavlov’s letters and accords of his contemporaries say he was a convinced materialist. At the same time he greatly valued religion as a way of conciliation and comfort for people in grief and as a moral guideline for uneducated minds. While he believed that a rational society would see no need for religion, he put the freedom of conscience and despised aggressive atheism.

Persecution of any kind and nature was in contrary with Pavlov’s moral standpoint, and he didn’t hesitate to oppose the soviet authorities. Shielded by his reputation and world fame, he protested the terror campaign. In a nonconformist gesture he wore medals and orders awarded to him by the tsarist government, which he didn’t do before the revolution. On the other hand, he was a steadfast patriot and refused to emigrate from Russia, even when the confusion of World War I, the revolution and the civil war left him with almost no conditions in which to conduct his research.

In his life and work Pavlov was a meticulous man sticking to schedules and focused on his goals – a quality he explained with a deliberate effort on his part, since it helped achieve better results. He was a brilliant surgeon with a rare and special technique. A dexterous man from birth, Pavlov trained his right hand for years and became ambidextrous, so much so that his assistants complained that his actions during operations were very quick and difficult to predict.

Pavlov was a scientist up to the last moments of his life. Reportedly lying on his deathbed with pneumonia, he made a secretary log his reports on how he felt his condition change. He asked to tell if anyone called on the telephone: “Pavlov is busy, he is dying.”

Pavlov’s work today:

Doctors throughout the world who treat patients with digestive problems use the knowledge gained through Pavlov’s research.

Pavlov’s work on behaviorism became its own separate science.

Pavlov’s humanitarian approach combined with his indefatigable courage was an example for many scientists in the Soviet Union.

Aleksandr Prokhorov was born in Australia in 1916 into a family of Russian immigrant revolutionaries who had escaped from Siberian exile. After the Bolsheviks took power in Russia and the turbulent years of the civil war were over, the family returned to its homeland in a striking contrast with so many people who fled the country at the time. In 1941 Prokhorov, a post-graduate student at Lebedev Institute of Physics in Moscow at that time, was conscripted into the army and spent four years fighting Nazi Germany. After his second injury, which left him handicapped, he was discharged and returned to research work.

He worked on non-linear oscillations and the stabilization of radio frequency, and then later switched to particle accelerators and their application as microwave generators. In the 1950s he met Nikolay Basov, who became his assistant in the laboratory of oscillations and later full colleague. Together they worked on improvement of frequency generators and radiospectroscopy. Eventually their research led them first to the creation of a microwave amplifier using quantum emission effects and later a generator – the “maser”.

The process behind lasers and masers is called stimulated emission and was theoretically proposed by Albert Einstein back in 1916. It is based on how matter can interact with photons. Electrons in an atom can jump from a lower energy level to a higher one by absorbing a photon with energy exactly corresponding to the difference between the two levels, i.e. if the radiation has a particular frequency. The atom becomes excited after it, and will eventually release the extra energy by emitting a similar photon, with the electron going back to the ground level, which is called spontaneous emission.

If another photon passes by an excited atom, it provokes the release of energy. What is more important, the new emitted photon will have exactly the same energy and direction as the one stimulating the emission. With enough excited atoms in a medium, a state called inversed population, the process develops into a cascade release of photons, like neutrons starting a chain reaction in a nuclear bomb.

The biggest problem is that inversed population is an unstable state, and normally the number of excited atoms is so low that there would absorb the extra photons and the would-be avalanche would stop. There are several ‘tricks’ that help avoid it. One is to remove atoms with ground state with a strong magnetic field. The principle was used in masers, devices for Microwave Amplification by Stimulated Emission of Radiation. The concept was first reported by Prokhorov and Basov in 1952. A year later, Townes created the first working maser, although it could only operate in pulses.

Another approach is to pump the medium with extra energy, which can be done by an electric discharge, strong radiation or a chemical reaction. It is used in masers working in the optical spectrum, better known today as lasers. Yet another one is using several energy levels so that only a small portion of atoms is involved in emission and absorption of photons, which was another idea suggested by Prokhorov and Basov. This allowed them create a maser working in a continuous mode.

Today there are many kinds of lasers from the super-powerful, able to cut through the hardest metals, to semiconductor lasers used in DVD players. Prokhorov and Basov contributed to the research in the technology. Prokhorov developed an open resonator – a couple of flat parallel mirrors bouncing back photons coming from the laser medium tuned to its frequency. Basov proposed the use of lasers for thermonuclear fusion control and for chemical reaction stimulation.

They both took part in the life of the scientific community. For example, Prokhorov was editor-in-chief of the Great Soviet Encyclopedia and other scientific reference books, while Basov chaired the country’s biggest educational society “Znanie” and worked in several scientific magazines.

Prokhorov and Basov’s work today:

Lasers in their many forms and applications are all based on their work.

Masers are used as high-precision frequency standards.

Dmitry Mendeleev was born in the city of Tobolsk, the unofficial capital of Siberia at the time, to a family of a school director and a daughter of merchant. He was 17th and the last one of his siblings, although this number is disputed. Shortly after graduating from St. Petersburg Institute of Pedagogy, Mendeleev was diagnosed with tuberculosis and traveled Southern Russia with its favorable climate where he worked as a schoolteacher. After recovering, he returned to the capital and received a Master’s in chemistry for his study of silicates at the age of 22.

Vladimir Kremlev for RT

In 1859 Mendeleev took a two-year journey to Germany and other European countries to meet leading scientists and learn from them. In 1865 Mendeleev became a Doctor of Science for his dissertation “On the Combinations of Water with Alcohol”. This work contributed to the birth of a popular legend, which claims that Mendeleev invented the standard for Russian vodka, saying it should contain 40% of alcohol by volume.

This is not true. The only connection the scientist had to vodka production was his work in a state commission on taxation of strong alcohol, while the 40% standard was imposed in 1843, when Mendeleev was nine years old. Mendeleev himself was not even fond of the drink, but was a devoted smoker, jokingly claiming that the smoke killed germs in his lungs. Another weakness was tea, which he specifically ordered from China and personally mixed at home.

Mendeleev’s greatest contribution to science is certainly the Periodic Table of Elements, which says the properties of basic elements repeat periodically when they are arranged by their atomic number. He made the discovery in 1869 during his work on the award-winning textbook on chemistry basics. The first edition of the book published a year later had the periodic table in it. Mendeleev’s further study resulted in prediction of the properties of elements that had not yet discovered at the time, like gallium or germanium.

Early version of the periodic table penned by Mendeleev

A popular legend says Mendeleev saw the periodic table in a dream, which is not true either. The origins of the myth are not known for sure, but it was probably due to the chemist’s impatient temper and his reluctance to explain for a hundredth time how he came up with the discovery. The actual work behind the breakthrough took years, if not decades.

A proponent of applied science, Mendeleev studied vigorously to improve production techniques in numerous areas. He helped build Russia’s first oil refinery, published theories on the origin of oil and predicted that it will become a key component of the world economy. He was the first one to suggest the idea of using pipelines for transportation of fuel in 1863.

A good example of Mendeleev’s lifestyle as a field researcher rather than a “bookworm professor” was his aerostat flight in 1887. The hydrogen aerostat was meant to lift the scientist high enough to have unobstructed view of a solar eclipse, a rare chance to study the solar corona. However the day of the event was rainy, the balloon got wet and too heavy to lift both the pilot and the scientist. A more vivid, albeit less accurate account says Mendeleev first threw out the pilot from the basket, then all the furniture, and went into the sky.

Scientifically the trip was in vain, the aerostat failing to rise over the clouds, but it was a success as a publicity stunt. The dramatic story of a famous scientist risking his life and forced to make repairs during his first ballooning experience was so daring that the French aerostat meteorology academy awarded him a medal for it. It is worth mentioning that meteorology was among the many areas of interest for Mendeleev.

He called for wider use of fertilizers in agriculture and tested various fertilizers on his own estate. Mendeleev’s collection of minerals was among the best in the country. He also invented several improvements to instruments and created a special instrument for measuring a liquid’s density. Serving as the head of Russia’s Bureau of Weights and Measures, he influenced the country’s transition to the metric system.

On a request of the Russian Navy, Mendeleev studied the European experience in production of smokeless gunpowder and developed his own compound he called “pyrocollodion” as well as helped develop the industry in Russia. It’s not clear why the formula was not adopted and French technology was imported instead. Some say it was due to competition among military officials, others cite rather strict requirements for the process proposed by Mendeleev. Nevertheless, a kind of gunpowder very much like his was mass produced in the United States during World War I and was even imported to Russia.

Mendeleev had a hand in the research of shipbuilding and Arctic maritime travel, thanks in large part due to his good relations with the famous explorer and the creator of the Russian semaphore code Admiral Stepan Makarov. Mendeleev helped create Russia’s first ship model basin for testing of ship designs. He also took part in designing world’s first Arctic icebreaker “Ermak”. The idea of making Russia’s northern territories accessible via sea was very appealing for Mendeleev, who strongly argued for more equal distribution of production facilities and population over the country.

Economy and social policy was one of Mendeleev’s favorite topics. He was a strong proponent of protectionism, promoted development of domestic industries, had ideas on how to relatively painlessly turn Russia’s traditional agricultural communities into a basis for a modern urbanized society. In early 1900s he made a study based on a recent nation-wide census with demographical estimates stretching forwards as far as 2050.

A devoted traveler, photographer and collector, Mendeleev was fond of crafting his own bags and suitcases. His serious approach to the hobby resulted in a legend, claiming that merchants in the market where he bought leather and fabric knew him as “Mendeleev, the famous suitcase master”.

Some of Mendeleev’s works were subject to controversy. His had skeptical attitude towards several scientific theories, like the studies of electrolytes, the discovery of the electron and radioactivity. Some biographers suggest that his criticism of “physical” ionic theory of conductive solutions conceived by Swedish scientist Svante Arrhenius contributed to his never receiving the Nobel Prize in Chemistry, despite his name being on the short list three times. Meanwhile Arrhenius did receive the award for the very theory Mendeleev criticized. Mendeleev was also a proponent of the erroneous “aether” concept and believed it to be an element preceding hydrogen in the arrangement he discovered.

Mendeleev’s personal life was also ridden with scandal when, at the age of 43, he fell in love with a 19-year-old woman and asked his first wife for a divorce. In Orthodox Russia divorce was both shunned and complicated. When the marriage was terminated, the church forbade Mendeleev from wedding again for six years, but he violated the prohibition to a great deal of public uproar and probably contributed to his failure to be elected into Russia’s Academy of Science at the time.

A popular anecdote says he had to plead Emperor Alexander III to permit the divorce. After it was finally put through, people unhappy with their spouses tried to follow lead, indicating Mendeleev’s case as a precedent. The monarch’s response reportedly was “I have plenty of you fools, and only one Mendeleev.” Again, the historical accuracy of this is very questionable.

Mendeleev’s work today:

The Periodic Table of Elements is a must know for any scientist today.

Reforms of the education system in Russia influenced by Mendeleev spurred engineering and technology to an unprecedented level.

Oil and gas pipelines – one of the key features of modern day geopolitics – are Mendeleev’s idea.