Summary: Louis Pasteur (1822–1895) was a world-famous French scientist, widely regarded as the Father of Microbiology. Born in Dole, France, he dedicated his entire life to the study of tiny living organisms called micro-organisms or germs. His groundbreaking research proved that germs — not spontaneous generation — are responsible for causing infectious diseases, a discovery that revolutionised the fields of medicine and public health. Pasteur also developed the process of pasteurisation, a method of heating liquids like milk and wine to kill harmful bacteria, which is still used worldwide today.
One of Pasteur’s greatest contributions to humanity was the development of the rabies vaccine. As a child, he witnessed a man who had been bitten by a rabid wolf, and the terrifying sight of that suffering never left him. Determined to find a cure, he conducted years of experiments on rabbits, isolating the rabies virus and successfully treating the infected animals by injecting them with a weakened form of the virus. When a young boy named Joseph Meister was brought to him after being severely bitten by a rabid dog, Pasteur courageously administered his new vaccine. The boy recovered completely, making him Pasteur’s first successful human patient and marking a turning point in the history of medicine.
In recognition of his extraordinary contributions to science and humanity, the French government founded the Pasteur Institute in Paris in 1888. The Institute is world-renowned for its research in biology, micro-organisms, diseases and vaccines. Louis Pasteur died in 1895, but his legacy lives on through the millions of lives saved by his discoveries. He is remembered not only as a brilliant scientist but also as a man of deep compassion who used his knowledge to relieve human suffering.
Word Meanings
| Word | Meaning |
|---|---|
| Micro-organism | A very small living thing that can only be seen under a microscope |
| Virus | A tiny living thing, too small to be seen without a microscope, that causes infectious diseases |
| Ailing | Sick or unwell; not getting better |
| Inflammation | A condition in which part of the body becomes red, swollen, and painful due to infection |
| Vaccine | A substance injected into a person or animal to protect them against a disease |
| Scratched | Skin cut or damaged slightly with something sharp |
| Frightened | Feeling fear or terror; scared |
| Deadly | Causing or able to cause death |
| Experiment | A scientific test done to find out what happens or to prove something |
| Treatment | Medical care given to a patient for an illness or injury |
| Pasteurisation | The process of heating a liquid (such as milk) to a high temperature and then cooling it quickly in order to kill harmful bacteria |
| Institute | An organisation founded for a specific scientific or educational purpose |
| Cure | A substance or treatment that makes a disease better |
| Infection | The process of being affected by a disease-causing organism |
| Rabies | A deadly viral disease that causes inflammation of the brain, madness, and death in humans and animals |
Comprehension Questions (Think and Answer)
1. (a) What happened one day while Louis Pasteur was playing with his friends?
Answer: One day while Louis Pasteur was playing with his friends, he saw a man come running towards him. The man was very frightened. He told them that someone had been bitten by a mad wolf from the mountain.
1. (b) What does rabies cause in human beings? What happens to a person suffering from rabies?
Answer: Rabies is a viral disease that causes inflammation of the brain in human beings. A person suffering from rabies goes mad and finally dies. It is an extremely painful and deadly disease.
1. (c) What experiment did Pasteur conduct on rabbits to find a cure for rabies?
Answer: Pasteur conducted experiments on rabbits to find a cure for rabies. He isolated the virus that causes rabies and then treated the ailing rabbits by injecting them with the same virus in a weakened form. He succeeded in curing the infected rabbits through this method.
1. (d) Who was Pasteur’s first human patient? Was his treatment successful?
Answer: Pasteur’s first human patient was a schoolboy who had been bitten by a mad dog. His treatment was successful. The boy slowly recovered completely from rabies after being given the vaccine by Pasteur.
1. (e) Where and when did the French government establish the Pasteur Institute? What is it famous for?
Answer: The French government founded the Pasteur Institute in Paris in 1888. It is famous for the study of biology, micro-organisms, diseases and vaccines. It is one of the most renowned scientific research institutions in the world.
Activity: Complete the Flowchart
Arrange the following events in order to show the cause and effect chain in the story of Louis Pasteur and his discovery of the rabies vaccine.
Answer: The correct cause-and-effect sequence of events is as follows:
- Young Pasteur sees a man who has been bitten by a rabid wolf from the mountain — the sight deeply affects him.
- Pasteur becomes determined to find a cure for rabies and begins scientific research.
- He conducts experiments on rabbits, injecting them with the rabies virus and successfully curing them.
- He isolates and weakens the rabies virus to create a vaccine.
- A schoolboy named Joseph Meister is severely bitten by a rabid dog and brought to Pasteur.
- Pasteur administers the rabies vaccine to the boy for the first time on a human being.
- The boy recovers fully — Pasteur’s vaccine is proven successful on a human patient.
- The French government recognises Pasteur’s achievements and founds the Pasteur Institute in Paris in 1888.
Vocabulary Activity: Word Web — Words Related to Disease
Find words related to disease from the lesson and note them in a word web.
Answer: The following words related to disease appear in the lesson:
- Rabies — a deadly viral disease causing brain inflammation
- Virus — a tiny micro-organism that causes infectious disease
- Inflammation — painful swelling of a body part due to infection
- Vaccine — a substance that protects against a disease
- Infection — the spread of disease-causing organisms in the body
- Cure — a remedy that makes a disease better
- Treatment — medical care given to a patient
- Patient — a person receiving medical care
- Ailing — sick and not recovering
- Micro-organism — a tiny living thing that causes disease
- Measles — a contagious viral disease
- Rubella — a viral disease dangerous to unborn babies
- Malaria — a disease spread by mosquito bites
Vocabulary Activity: Match the Words with Their Meanings
Match the words from Column A with their correct meanings in Column B.
| Column A (Word) | Column B (Meaning) |
|---|---|
| Micro-organism | A very small living thing that can only be seen under a microscope |
| Virus | A living thing, too small to be seen without a microscope, that causes infectious diseases |
| Ailing | Sick and not improving |
| Scratched | Skin cut or damaged slightly with something sharp |
| Inflammation | A condition in which part of the body becomes hot, red, swollen, and painful |
| Vaccine | A substance given to protect a person or animal against a disease |
| Frightened | Feeling fear; scared |
Dialogue Completion Activity — Diseases and Their Effects
Five friends are sharing information about different diseases. Complete the dialogues using information from the lesson and your own knowledge.
Puja: Beware of animal bites. You may get rabies. What do you know about this disease?
Answer: Rabies is a deadly viral disease caused by a virus that attacks the brain. It is usually spread through the bite of an infected animal such as a dog, wolf, or fox. Rabies causes inflammation of the brain in human beings. A person suffering from rabies goes mad and finally dies if not treated immediately. The rabies vaccine, developed by Louis Pasteur, is the most effective way to prevent and treat this disease after a bite from a rabid animal.
Rohan: I heard that measles is a very deadly disease. What do you know about it?
Answer: Measles is a highly contagious viral disease. It spreads easily from one person to another through coughs and sneezes. Its symptoms include high fever, rash on the skin, runny nose, and red eyes. Measles is a deadly disease as it can lead to serious complications such as pneumonia, diarrhoea, and other life-threatening conditions, especially in young children. Vaccination is the most effective protection against measles.
Pushpa: What is rubella and why is it considered dangerous?
Answer: Rubella, also called German measles, is a contagious viral infection. It is generally a mild disease in children and adults, but it is extremely dangerous during pregnancy. If a pregnant woman gets rubella, the infection can spread to her unborn baby and cause serious congenital birth defects. These defects can include blindness, deafness, mental retardation, and congenital heart defects. This is why rubella vaccination is very important for all children and women of childbearing age.
Jumon: What is malaria and how does it spread?
Answer: Malaria is a serious and sometimes fatal disease caused by a parasite. It spreads through the bites of infected female Anopheles mosquitoes. When the mosquito bites a person, it injects the malaria parasite into the bloodstream. Symptoms of malaria include high fever, chills, sweating, and headaches. Malaria can be prevented by using mosquito nets, applying insect repellent, and taking anti-malarial medicines. Eliminating stagnant water where mosquitoes breed is also an important preventive measure.
Grammar: Active Voice and Passive Voice
Understanding Active and Passive Voice:
When the subject of a sentence performs the action, it is called Active Voice. When the subject receives the action (i.e., the action is done to the subject), it is called Passive Voice.
Example from the lesson:
Passive Voice: “Someone has been bitten by a mad wolf from the mountain.”
Active Voice: “A mad wolf from the mountain has bitten someone.”
Exercise: Change the following sentences from Active Voice to Passive Voice or Passive Voice to Active Voice.
(i) Active: Louis Pasteur conducted experiments on rabbits.
Answer: Passive: Experiments on rabbits were conducted by Louis Pasteur.
(ii) Active: He treated the ailing rabbits by injecting them with the virus.
Answer: Passive: The ailing rabbits were treated by him by injecting them with the virus.
(iii) Passive: The Pasteur Institute was founded by the French government in 1888.
Answer: Active: The French government founded the Pasteur Institute in 1888.
(iv) Passive: A schoolboy was bitten by a mad dog.
Answer: Active: A mad dog bit a schoolboy.
(v) Active: Pasteur saved the life of the boy.
Answer: Passive: The life of the boy was saved by Pasteur.
(vi) Passive: The rabies virus was isolated by Pasteur.
Answer: Active: Pasteur isolated the rabies virus.
Grammar: Simple Present and Present Continuous Tense
Understanding Simple Present and Present Continuous:
The Simple Present tense is used for habitual actions, universal truths, and permanent situations (e.g., “The sun rises in the east”). The Present Continuous tense (is/am/are + verb-ing) is used for actions happening at the moment of speaking or around the present time (e.g., “The baby is sleeping”).
Exercise: Complete the sentences using the Simple Present or Present Continuous form of the verbs given in brackets.
(i) We ____________ football in the afternoon. (play)
Answer: We play football in the afternoon.
(ii) The sun ____________ in the east. (rise)
Answer: The sun rises in the east.
(iii) Don’t make a noise; the baby ____________. (sleep)
Answer: Don’t make a noise; the baby is sleeping.
(iv) Someone ____________ at the door; can you hear it? (knock)
Answer: Someone is knocking at the door; can you hear it?
(v) The man ____________ towards the bus. (run)
Answer: The man is running towards the bus.
(vi) The bus usually ____________ at 8 o’clock. (come)
Answer: The bus usually comes at 8 o’clock.
Grammar: Simple Past and Past Continuous Tense
Understanding Simple Past and Past Continuous:
The Simple Past tense is used for completed actions in the past (e.g., “Pasteur died in 1895”). The Past Continuous tense (was/were + verb-ing) is used for actions that were in progress at a specific time in the past, or that were interrupted by another action (e.g., “He was playing when a man arrived”).
Exercise: Complete the sentences using the Simple Past or Past Continuous form of the verbs given in brackets.
(i) Louis Pasteur ____________ in 1895. (die)
Answer: Louis Pasteur died in 1895.
(ii) Pasteur knew that the mad wolf ____________ from rabies. (suffer)
Answer: Pasteur knew that the mad wolf was suffering from rabies.
(iii) When I reached his house, he ____________ lunch. (have)
Answer: When I reached his house, he was having lunch.
(iv) I ____________ at the station last evening. (arrive)
Answer: I arrived at the station last evening.
(v) The boys ____________ football when it suddenly began to rain. (play)
Answer: The boys were playing football when it suddenly began to rain.
Multiple Choice Questions (MCQs)
1. What disease did Louis Pasteur find a cure for?
Answer: (iii) Rabies
2. What animal did Pasteur experiment on to develop the cure?
Answer: (ii) Rabbits
3. What did Pasteur inject into the boy who was bitten by a mad dog?
Answer: (iii) The rabies virus (in a weakened form as a vaccine)
4. In which year was the Pasteur Institute founded?
Answer: (iii) 1888
5. Where was the Pasteur Institute established?
Answer: (iii) Paris
6. What did rabies cause in animals and humans?
Answer: (iii) Madness and death
7. Why did Pasteur become interested in curing rabies?
Answer: (ii) He saw a man bitten by a mad wolf in his childhood
8. What made Louis Pasteur world-famous?
Answer: (iii) His successful treatment of a boy bitten by a mad dog using the rabies vaccine
9. When did Louis Pasteur die?
Answer: (iii) 1895
10. What is a vaccine?
Answer: (iii) A medicine or substance given to protect a person against a disease