THREE GREAT MICROBIOLOGISTS

Louis Pasteur

The scientific contribution of Louis Pasteur, French microbiologist is among the most valuable in the history of science. He was born 1822 at a small village in eastern France. His father and grandfather were tanners and yet as a boy he got knowledge in chemical treating of hides. One day he saw a rabid dog to run through the village and to bite a neighboring peasant. In spite of burning the wound in the near smithy the peasant died in some days. Young Louis was very impressed by this event and he swore to make everything to battle the disease.

After finishing the primary school Pasteur was admitted to the famous Ecole Superieure in Paris. Having graduated this higher school he taught chemistry and physics at different schools and began his scientific research on fermentation and development of bacteria. He determined that fermentation was the result of the activity of minute organisms. Pasteur showed that milk or beer could be soured by invading a number of such organisms. Besides he was dealing with medical problems, his interest turned to the structure of blood and blood transfusion. He suggested as a first the group classification of human blood and tried to precede it for transfusion to wounded soldiers on the front during the French-Prussian war 1870. Due to scoundrel deeds of his enemies it failed. Pasteur had to escape to Britain where he continued the works on beer. Following an investigation conducted both in France and by brewers in London he devised a procedure for manufacturing beer that would prevent its deterioration with time. British exporters were able to send beer even as far as India without fear of its deteriorating.

Having returned to France Pasteur perfected a technique for reducing the virulence of various disease-producing microorganisms. He had observed that if animals stricken with certain diseases had recovered, they became later immune to a new attack. Thus by isolating the germ of the disease and by cultivating its weakened form to be later inoculated, he could immunize animals against maladies. He succeeded in vaccination a herd of sheep against anthrax. Likewise he was able to protect fowl from chicken cholera. By further work he could obtain a weakened form of the virus that could be used for inoculation. Having detected the rabies virus by the effect on the nervous system, he applied this procedure to man. 1885 he saved the life of a boy who had been bitten by a rabid dog.

That was Pasteur¢s victory over rabies, an outstanding success. Pasteur was awarded many decorations, and he became a head of the special Research Institute named after him. And now he is regarded as one of the greatest personalities in France.

Задание 73. Расскажите о достижениях Луи Пастера, ответьте на вопросы: 1. Why are bacteria dangerous for people? 2. What dangerous disease could overcome Louis Pasteur? 3. What is the principal content of vaccination? 4. What is the meaning of the term “pasteurization”?

Robert Koch

Robert Koch was a prominent German bacteriologist, the founder of modern microbiology. He was born in 1843. As a boy he was interested in small insects and animals and collected them in his room. He observed details through the magnifying glass, because he wanted to know everything about the inner structure of animal¢s body. Once as he tried to cut a rat on the dining table a big quarrel arose between him, his brother and parents. Only his uncle supported Robert¢s occupations. He helped him to become a medical student of the famous Gottingen University. When Koch became a doctor he carried on many experiments on mice in his laboratory. In 1882 Koch discovered tuberculosis bacilli. In his report made in the Berlin Physiological Society Koch described in detail the morphology of tuberculosis bacilli and the ways to reveal them. Due to his discovery Koch became known all over the world. In 1883 he went to Egypt to study cholera. At that time there was a wide-spread epidemic of this terrible plague. Nobody knew the origin of this disease; there were not any protective measures against it. The disease spread very rapidly from one place to anoth­er and thousands of people died. But sometimes some people who were in a constant contact with the dis­eased person did not catch cholera. As soon as Koch began his investigations he found in blood, kidneys, spleen, liver and lungs of the people who died of cholera many microorganisms but all of them were not the agents of cholera. However in the walls of the intestines and in stools Koch always found an organism which looked like a comma. Many times Koch tried to grow this bacterium on gelatin but he failed to do it. Many times he inoculated this bacterium to the experimental animals, but none became ill. As the epidemic of cholera became less in Egypt, Koch went to India to continue his investigations there. In Calcutta Koch often walked along its muddy streets, where the poor people lived. Once Koch saw some muddy water on the ground near a small house. He looked into that water and thought there may be different bacteria to be analyzed. He did it under the microscope and found there the same “commas” which he had observed many times before. In 1884 Koch published his book on cholera. From the intestines of the affected men Koch isolated a small comma-shaped bacterium. He proved that these bacteria spread through drinking water. Later Koch experimented with other infectious agents and could isolate germs of such dangerous epidemic like anthrax. In 1905 Koch got the Nobel Prize for his important scientific discoveries.

Задание 74. Расскажите о работах Роберта Коха. Ответьте на вопросы: 1. Which bacteria were investigated by Koch and named after him? 2. What does occur when bacteria invade the human organism? 3. Which dangerous epidemic followed Koch in Egypt and India? 4. Is cholera possible in animals?

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