I. Read the text b, translate it and tell what you have learnt from this text:

Text B The Discovery of Cholera Bacterium

In 1883 Koch went to Egypt to study cholera. At that time there was a wide-spread epidemic of cholera in Egypt. 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 healthy people died. But sometimes some people who were in a constant contact with the diseased person did not catch cholera.

As soon as Koch came to Alexandria he and his two assistants began their investigations. In the blood, kidneys, spleen, liver and lungs of the people who died of cholera Koch found 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 a microorganism which looked like a comma. Many times Koch tried to grow this bacterium on gelatin but he failed to do it. Many times Koch inoculated this bacterium to the experimental animals but none became ill with cholera. 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 lived. Once Koch saw some muddy water on the ground near a small house. Koch looked into that water and thought he saw those “commas” there. He took some of this water, analyzed it under the microscope many times and found there the same bacteria which he had so many times revealed in the people with cholera. Koch also established that animals could not catch this disease. The source of the disease was the water which people drank.

II. Read the text c and give a short retelling.

Text C. Edward Jenner

Edward Jenner was born in 1749. He was an English physician, the discoverer of vaccination. Jenner studied medicine in London. He began practice in 1773 when he was 24 years old.

Edward Jenner liked to observe and investigate ever since he was a boy. His persistent scientific work resulted in the discovery of vaccination against smallpox. For many years every infant when it was about a year old was vaccinated against this disease. The vaccination was effective for a prolonged period of time. Now vaccination against smallpox is not carried out because this disease has been stamped out (искоренять) in our country.

In Jenner’s days one out of every five persons in London carried the marks of this disease on his face. But there were few people who recovered from the disease, because in the 18^th century smallpox was one of the main causes of death.

The disease had been common for centuries in many countries of Asia. The Turks had discovered that a person could be prevented from a serious attack of smallpox by being infected with a mild form of the disease.

One day Jenner heard a woman say:”I cannot catch smallpox, I’ve had the cowpox (телячья оспа)”. That moment led to Jenner’s continuous investigations and experiments.

The first child whom Jenner introduced the substance from cowpox vesicles (пузырёк) obtained from the wound of a diseased woman was Jimmy Phipps. It was in 1796. For the following two years Jenner continued his experiments. In 1798 he published the report on his discovery. He called his new method of preventing smallpox “vaccination”, from the Latin word ‘vacca’ that is “a cow”.

At first people paid no attention to his discovery. One doctor even said that vaccination might cause people to develop cow’s faces.

But very soon there was no part of the world that had not taken up vaccination. Thousands of people were given vaccination and smallpox began to disappear as if by magic.