Class 12 English Notes Chapter 14 Louis Pasteur

Class 12 English Notes Chapter 14 Louis Pasteur Punjab all boards Grade 12 FSc Pre Engineering include solved exercises, review questions, MCQs, and chapter overview.

Chapter 14 Louis Pasteur Class 12 English Notes

Q 1. Describe the early life of Pasteur.

 Louis Pasteur was born in Dole in the Jura district of France in 1822 in quite humble circumstances. His father had been a soldier in Napoleon’s army and had received great honours for his bravery and loyalty. When he was two years old, his family moved to Arbois, where he was sent to school at Communal College. At first, he did not take interest in studies but he soon developed the passion for work. He graduated in Science and Arts from the college at Besancon. Pasteur got the strength of his character and love for his country from his father.

Q 2. Give some instances of Pasteur’s patriotism.

Many instances indicate that Pasteur was more of a patriot than a scientist. For example, in 1848, when Europe was politically upheaved, Pasteur enrolled himself in the National Guard. Moreover, when he found out that donations were being collected for the motherland, Pasteur gave away all the money he had, which was one hundred and fifty francs. He applied for the enrollment again in 1870 while France was on the verge of war with Germany. However, to his disappointment, the military authorities refused to enroll him because he was partially paralysed at that time.

Q 3. What do we mean by spontaneous generation?

Spontaneous generation means the rapid growth of germs in an automatic way. Before Pasteur’s experiments on the spontaneous generation, scientists firmly believed that some of the living beings take birth from pre-existing non-living organisms. This is known as the theory of spontaneous generation. Pasteur did experiments and proved that it was not possible.

Q 4. How did Pasteur prove that spontaneous generation was not a fact?

Pasteur proved that spontaneous generation was not a fact by conducting experiments. He found out that if a substance is sufficiently heated to destroy all life and the air in contact with it is filtered so that it is free of germs, then the substance does not alter because bacteria do not develop in it.

Q 5. Describe the importance and popularity of the silkworm industry in France. What help did Pasteur render in curing the silkworm disease in his country?

The importance of the silkworm industry in France lies in the fact that keeping of silkworms was the chief home industry of the peasants. Every family set up the best room in the house for rearing silkworms and women would get up at night to feed the worms with fresh mulberry leaves and check if the temperature of the room was appropriate. Their social greeting was not asking each other how their silkworms were doing, which clearly speaks of the popularity of the silkworm industry in France. Pasteur rendered great help in curing the silkworm disease in his country by discovering its causes, such as over-crowding, uncleanliness, over-heating etc. He also suggested the remedy to cure the disease. Hence, Pasteur compensated the national loss of forty million francs with his efforts.

Q 6. How did Pasteur discover the treatment for the cattle disease, Anthrax?

Pasteur discovered the treatment of the cattle disease, Anthrax by cultivating anthrax bacillus in a way that it became mildly poisonous. He injected it into the animal’s blood. As a result, its body developed a protective system and it indicated very few symptoms of the disease.

Q 7. How did Pasteur discover the method of making vaccines?

When Pasteur returned to his lab after a holiday, he found all the cultivations of the germs to be either dead or dying. He injected various birds with those dead or dying germs and found that the birds showed a few symptoms of illness, but recovered. Then, he injected birds with fresh germs of chicken cholera and he was amazed to see that they showed mild symptoms of the disease, while those birds, which had not been injected with exhausted germs, died. In this way, Pasteur discovered the method of making vaccines in 1879.  

Q 8. Give an account of Pasteur’s treatment of Hydrophobia and how he cured the first patient suffering from it.

Pasteur tried taking some of the nervous tissue of an animal, which had died of the disease. He weakened it by exposing the spinal cord of the rabbits to dry air until after fourteen days, it was found harmless. When he introduced the attenuated spinal cord into dogs, they became immune to hydrophobia. In this way, Pasteur discovered the treatment for Hydrophobia. He cured the first patient suffering from hydrophobia, who was a boy, named Joseph Meister bitten by a mad dog two days before the treatment started. He brought him to Paris and injected him with the vaccine for ten days until he was cured.

Q 9. How did Pasteur show the way to other scientists? Give an account of the discoveries.

The fame of Pasteur’s discoveries stirred up other scientists to try similar methods for the cure of other diseases. Between 1880 and 1890, they discovered the germs of consumption, diphtheria, typhoid, lockjaw, cholera, and Malta fever. In this way, Pasteur was able to show the way to other scientists. His discoveries include the vaccination for the silkworm disease and penicillin for the cure of wounds and vaccination for the treatment of human diseases like anthrax and hydrophobia.

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