Discovery of Microbes
The discovery of microbes and the fact that they cause infectious diseases is one of the greatadvances in science, which has helped us in understanding, preventing and eradicating various diseases. Before this no-one had imagined that such tiny creatures could create havoc in the life of human beings. Antonie van Leeuwenhoek, a-Dutch, was an expert in making lenses. He was the first person to observe bacteria about 300 years ago. Out of curiosity, he examined the waterof marshy lakes, rain water. human excreta and scraping from his own teeth and was astonished to find tiny living creatures in them. He named them "animalcules". They spun about like a top or darted through water like little fish in a pond. He was perplexed, and he pondered about their origin and role. He sent his observations to the Royal Society of London. The Queen of England also came to see these "animalcules". van Leeuwenhoek also made another significant observation that the scraping from teeth. if examined soon after drinking hot coffee, contained only dead animalcules. His observations could not be explored further by other scientists because he was a very suspicious and secretive person and did not teach anyone else to make lenses.
Another class of microbes were observed in the eighteenth century. but scientists took them as idle curiosities of nature, because to blame disease on micro-organisms was to break with century old tradition rooted in religious beliefs and dogmas. In the middle of the nineteenth century, a famous French scientist, Louis Pasteur showed that where disease was rampant, air was full of microbes, but where the air was clean. disease was uncommon. He also established that diseases were due to germs. A few years later Robert Koch of Germany showed that a specific kind of bacteria is responsible for anthrax. another for tuberculosis, a tliird for plague etc. This splendid work motivated many scientists to identify and study bacteria that were responsible for various diseases. It was found that malaria is caused by protozoan called "plasmodium" which is carried by the female mosquito Anopheles. Their findings often led to posiible cures of the diseases. Thus, the mystery of disease was unfolded.
It is worth giving a thought that if the first discovery of Leeuwenhoek was followed up instead obeing ignored because it went against established beliefs, perhaps millions of lives could have been saved. Another class of microbes are virus. Common cough, cold, and viral fever which afflict .many people these days, are caused by them. They are smaller than bacteria and therefore remained a mystery till late in the nineteenth century. Virus cannot be seen with low power microscopes; they were observed only when more powerful microscopes were invented. Virus are strange objects because they behave like chemical molecules, and cannot replicateoutside the living cell of the host animal. They can be crystallised like sugar or salt. But on invading the host cell, they behave like a living organism and replicate like bacteria, to causefever or other diseases. During the Industrial Revolution, Edwin Chadwick (1800- 1890) demonstrated a close connection between disease and poor sanitqry conditions. Hence, it was clear that many diseases depended on the conditions of living, which human beings experienced in society. not because they had sinned and were being punished.