ids Org. Louis Pasteur and his germ theory

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By Manju Gupta

LOUIS PASTEUR, the French chemist and founder of the science of microbiology, was born on December 27, 1822 to a poor tanner in Dole, France. He had to ration his food and firewood to the barest level possible, frequently suffering from hunger pangs. In his later years, when asked how he survived thus, Pasteur replied, “Fortunately, I was also a subject to frequent headaches, so one pain tended to cancel out the other.”

It was with great financial difficulty that he went on to study for his doctorate in chemistry. Pasteur'spersistence in love was no less than his persistence in studies. On being turned down by the girl he loved, he wrote to the young girl'smother, “I am afraid that Medemo-iselle Marie attaches too much importance to first impressions, which can only be unfavourable to me. There is nothing in me to attract a young girl. But memory tells me that when people have known me well, they have liked me.”

It was Pasteur'swedding day. His bride and her family were chewing off their fingernails in panic when he did not show up. The pastor shouted, “Where on earth is that young chemist?” Where could he be except in his laboratory, thought a friend of Pasteur as he hurried to the lab to see if he was there. The unruffled groom was plunged deep in one of his experiments. “Did you forget your wedding?” asked the friend. “Oh no!” replied Pasteur. “But do you expect me to quit in the middle of an experiment?”

He received his education at the Ecole Normale Superieure in Paris and he worked as professor of chemistry at Strasbourg. He would teach his disciples,“Do not put forward anything that you cannot prove by experimentation.” He then returned to Ecole Normale as Director of Scientific Studies. His first discoveries were made in crystallography.

In 1857, Pasteur first presented his germ theory in which he claimed that as in fermentation, diseases were caused by microbes. He then went on to show that in reality each microbe is derived from a similarly pre-existing microbe and that spontaneous generation does not occur, unlike what was earlier believed. He demonstrated that spoilage of perishable products could be prevented by destroying or excluding the microbes already present in the products and by protecting the material against further contamination. His work overturned the concept of spontaneous generation (life arising from non living matter) and led to heat pasteurisation, allowing wine, vinegar and beer to be produced and transported without spoiling.

In 1865, Pasteur was asked to study diseases of silkworms that threatened the silk industry. After toiling for three continuous years, he discovered two distinct diseases in silkworms and showed how they could be prevented. This way he saved the French silk industry from a calamity. While conducting his investigations on the silkworm epidemic, three of his children died in succession. His friend said to Pasteur, “To persist with your work under such trying conditions must require a lot of courage.” Pasteur replied, “I don'tknow much about courage. But I do know my duty.”

In 1877 he demonstrated that a particular bacillus was responsible for causing anthrax. The bacillus can survive in the carcasses of dead animals. In 1881, he perfected a way to isolate and weaken germs and went on to develop vaccines against anthrax in sheep and cholera in chickens following Edward Jenner'sexample.

In 1882 Pateur turned his attention to researching on hydrophobia. His experiments used to consist of inoculating the saliva of mad dogs into healthy rabbits, by allowing them to be bitten by the mad dogs. On one occasion, a large, ferocious bulldog refused to comply. Pasteur decided to suck in the saliva out of the dog'smouth himself. His assitants tied the dog securely and Pasteur, with a glass tube in his mouth, bent close to the jaws of the animal. Very coolly and fully aware that even a tiny drop of the deadly liquid would kill him, he sucked into the tube. When he thought he had pulled out a sufficient amount, he calmly turned to his assistants to say, “Well gentlemen, we can now proceed with the experiment!”

In 1888, he was appointed the first Director of the newly established Pasteur Institute. He was even elected by the French government to represent at the International Congress in London. He entered St. James Hall amidst tumultuous applause, blissfully unaware that he was the cause of ovation. He turned to his escort to apologise, “It must be the Prince of Wales arriving. I?m sorry, I didn'tcome earlier.”

Gradually his health began to fail, but he continued with his reasearch till his death in 1895 as he believed that spiritual values transcended science, giving meaning to his work.