A Story of Louis Pasteur

More than hundred years ago, a French boy called Louis Pasteur was playing with his friends in Arbois, the little town that was his home. Suddenly there came a sound of running feet and voices of people shouting. Louis looked up. “What has happened?” he asked a man standing near him.

Someone has been bitten,” said the man. “By a mad dog?” asked Louis. The man looked frightened. “No,” he said, “not a dog – a wolf. A mad wolf came down from the mountains.” Louis hurried home. A mad wolf! He too felt afraid, and he was glad to reach the safety of the house.

The mad wolf was suffering from a disease called rabies, then common in France, and the man who had been bitten would probably take the disease, and suffer terribly, and die.

Louis did not forget that day; though he did not then know that later in his life he would discover a way of preventing the disease.

A Story of Louis Pasteur

When Louis left school, he trained himself as a scientist. He won a place at the famous Ecole normale superieire. At first he worked at problems in chemistry, making discoveries for which he became famous.

Soon he began to interest himself in such questions as: what makes wine and beer ferment? Why do wine and beer sometimes go sour? And what sours milk?

He discovered that when milk, wine, or beer sours, the change is brought about by the presence of certain bacteria, very, tiny and simple living things that cannot be seen with the naked eye. Pasteur was able to observe them through his microscope.

He found that the bacteria that cause souring could be killed by heat, by raising the temperature a certain amount for a certain length of time.

Heat treatment of wine, beer, milk, etc. is still carried out today, and, in honor of Pasteur, it is known as pasteurization. We know that pasteurization destroys not only bacteria that cause souring but also germs that cause disease in human beings.

Another field in which Pasteur worked as a scientist was the study of disease germs. The germs of certain diseases are bacteria, but other diseases are caused by viruses, which are too small to be seen with the kind of microscope that was in use on Pasteur’s time.

Pasteur studied a number of animal diseases. One of theses was anthrax, a disease that can also be contracted by men. At that time (1881) anthrax killed many sheep and cattle in France. Pasteur discovered how to grow anthrax bacteria that were much less powerful than those found in diseased animals.

He showed by experiment that if animals were inoculated with the weakened bacteria and then infected with really powerful bacteria, they would not die.

Pasteur’s idea of protecting people against disease by inoculating them with much weakened bacteria or viruses (nowadays. In some cases, with dead bacteria) had been worked upon by other scientists, and today we can be inoculated against typhoid, diphtheria, and other diseases.

But Pasteur himself had other great discoveries to make in this field, the most important being the discovery of how to prevent rabies. He had never forgotten the man in Arbois who was bitten by the mad wolf.

The germ that causes rabies is a virus too small to be seen under an ordinary microscope. The disease may affect dogs, wolves, jackals, other animals and men.

Pasteur removed the infected parts of rabbits suffering from rabies and, by treating these parts, obtained the virus in a weakened form.

With this he inoculated animals. Some he inoculated before causing them to be bitten or otherwise infected. Some he inoculated after they had received an injection of the rabies germs. In both cases the animals remained healthy, and did not develop the terrible symptom of the disease.

So far, Pasteur’s patients had been animals. He had not ventured to try his methods on human beings, for it was by no means certain that the treatment would have the same effect on them as on animals.

Then one day – the sixth of July 1885, a very memorable day for Pasteur – a woman came to him in great distress, with her son Joseph Meister. “Save my son!” She cried, “Save him, sir! A mad dog had bitten him.”

The boy had indeed been badly bitten. But even so, it was not absolutely certain that he could contract the disease and die. What was Pasteur to do? Should he try on a human being the treatment that had been so successful with animals?

He decided that he must.

He took the boy into his own home so as to watch him carefully, and gave him a series of inoculations. He waited anxiously to see what would happen. At last the danger period had passed. The boy was well and strong again. A method of preventing rabies had been found!

Pasteur’s fame spread, funds flooded in, and he received honors from many countries. In 1888, the French Government founded the Pasteur Institute in Paris. Here further experiments could be carried out and patients could go to be treated. Pasteur was the founder of bacteriology as practical science.