Microbiology and Microscope
Kolkata, West Bengal
Invisible to the eye, but present in water, soil, and air. Infections arise from the attack of these invisible entities. But how do they occur, and what exactly are these microbes?
It took several centuries to understand. Microbes are tiny organisms (Microorganisms). They can’t be seen with the naked eye, but with a microscope. The microscope’s lens revealed their existence. Bacteria, protozoa, fungi—these are all microscopic organisms. Viruses also belong to this category, though some argue that viruses are non-living.
Understanding microbes required centuries of research. About three and a half centuries ago, we first learned that tiny creatures work beyond our vision. This revelation didn’t come from a scientist but a businessman. By inventing a device, he demonstrated the existence of these invisible creatures. The man was Antonie Philips Van Leeuwenhoek (1632–1723). As a merchant, he inspected the quality of silk fabrics using glass. Gradually, he polished glass to create high-quality lenses. With these, he made a simple microscope, a tool to magnify small things. Looking through the lens, he saw strange things. Numerous small creatures wiggling in water. What were these? He named them animalcules. He also found them in blood. In Holland, Leeuwenhoek polished glass to make lenses and, though not a scientist, created A simple microscope.
Without the invention of the microscope, science wouldn’t have advanced. The device taught us microbiology and showed us that microbes possess a strong life force. They survive in hot springs, seven miles deep in the ocean, and forty miles above the earth. Some even live without oxygen. Microbes attack when given the opportunity, meaning they quickly multiply once inside the body. Typhoid, cholera, malaria, even colds, are caused by microbes. Animals too fall prey to microbial attacks.
The microbial kingdom, especially bacteria, is significant. While many bacteria cause diseases, some have beneficial properties. The Lactobacillus bacteria help make curd from milk. Many oceanic bacteria (Cyanobacteria) produce half of the Earth’s oxygen. Bacteria (Azotobacter, Rhizobium) decompose waste and dead bodies, enriching the soil. Many beneficial bacteria aid human digestion (E. Coli). Bacteria are single-celled and, surprisingly, lack a nucleus.
After Leeuwenhoek, more advanced microscopes were invented. English scientist Robert Hooke (1635-1703) created the compound microscope. He used his device to observe tiny organisms. Contemporary with Isaac Newton, Hooke is known for ‘Hooke’s law’ in physics. His book ‘Micrographia’ (1665) stirred biological history. Observing cork with his microscope, he discovered numerous chambers (cells) within. Hooke coined the term ‘cell’ and revealed that living bodies are made of countless cells. This discovery led to intense research, and now even school children know that plant and animal bodies are made of numerous cells.
Leeuwenhoek and Hooke’s discoveries answered many ancient questions. For example, why does food or fruit rot? The answer is microbes. The next question: do microbes generate spontaneously?
Before Leeuwenhoek’s discovery (1675), people had no idea why food, fruit, or dead bodies rotted. Even he didn’t understand the connection between decay and microbes. He only proved the existence of countless tiny active creatures hidden from view, visible only through a microscope.
How do microbes appear in food left out? French scientist Louis Pasteur (1822–1895) found the answer through ten years of research. He proved that microbes enter food from the air or dust.
Leeuwenhoek, Robert Hooke, and Louis Pasteur’s 200 years of research revealed that microscopic organisms are present in water and air. However, proving that they cause disease took much longer.
German scientist Robert Koch (1843–1910) demonstrated that microbes cause many diseases. He found a type of bacteria (Bacillus anthracis) in the blood of cows with anthrax. Injecting this blood into healthy cows made them sick. Koch later discovered the cholera bacterium (Vibrio cholera). He also researched tuberculosis, identifying the causative bacterium (Mycobacterium tuberculosis), earning a Nobel Prize in 1905 for this discovery.
While some microbes are harmful, others are beneficial. Preventing harmful microbial infections is essential. Primary measures include keeping the environment and water free from microbes. Therefore, brushing teeth, bathing with soap, washing hands, and avoiding stale food are simple but crucial health guidelines.
However, microbial activity is so complex that infections occur despite precautions, leading to serious, sometimes fatal, diseases. Though antibiotics have been discovered to combat microbial infections, deadly diseases persist.
Building on 350 years of microbial knowledge, many new discoveries have been made. For example, by inserting the human insulin gene into bacteria (E. Coli), commercial human insulin is produced. Microbes can alter the genetic traits of many plants and animals. Microbial research continues to yield essential discoveries. Medicine, food, and even artificial organs are now possible.
Today, microbiology is a highly valuable branch of science. Its pioneer was not a scientist but a diligent individual with advanced intelligence and observation skills. He passed away 300 years ago at the age of 90. In the past century, there has been remarkable progress in the world of microscopes. However, the credit for the first microscope goes to Antonie Van Leeuwenhoek, a businessman.
Leeuwenhoek’s microscope
Robert Hooke’s drawing of cork. The small chambers are cells.
References -
1. Microbe Hunters (1954), Paul de Kruif, Harcourt Brace Jovanovich, Publishers, San Diego.
2. The Development of Microbiology (1976), P. Collard. Cambridge University Press, Cambridge.