Category Great Scientific Discoveries

          William Harvey’s description of the circulatory system could not explain how blood moved from arteries to veins. This was one of the mysteries solved by the invention of the microscope.

          In 1661, Marcello Malpighi was working in Bologna, Italy when he discovered tiny vessels through which blood travels. These tiny vessels known as capillaries could only be seen using a microscope and they proved to be the missing element in Harvey’s theory.

          Capillaries are the smallest blood vessels in the human body which function as the site of exchange for many substances. While substances such as water, oxygen and glucose exit the body, other items including, water, carbon dioxide, uric acid, lactic acid, urea and creatine enter the bloodstream through capillaries.

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         What are the constituent elements of all living things? This centuries old question was answered only in the 1660s when scientists Anton Van Leeuwenhoek and Robert Hooke discovered cells and their parts.

         While observing a piece of cork, Hooke noticed that it was made of small structures that reminded him of individual rooms. What appeared like rooms to him were called cells. Meanwhile, Anton Van Leeuwenhoek studied substances such as blood and saliva under the microscope. Within these, he observed tiny parts which he named “animalcules” as they resembled animals.

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          Robert Hooke and Anton Van Leeuwenhoek discovered the existence of microscopic organisms between 1665 and 1683. The presentation of the micro fungus Mucor in Hooke’s Micrographia (1665) is the first published depiction of a microorganism. In 1674, Leeuwenhoek became the first person to see the tiny, single-celled protozoa that swim around in ponds and water butts.

          The organisms discovered until then were comparatively larger than those like bacteria, which were even smaller than protozoa. In 1676, Leeuwenhoek made a lens that could magnify up to 280 times. Using this lens, he observed some of the larger types of bacteria collected from his mouth. Leeuwenhoek used certain techniques to watch them. These techniques probably involved lighting the microscopic organisms from a side, so that they would stand out like dust in a sunbeam.

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          We all know that plants cannot live without the sun. Plants around us absorb energy from sunlight to make food from water and carbon dioxide. This process is called photosynthesis. Though this phenomenon has existed since time immemorial, humans were ignorant about it until the 1800s.

          When green plants receive sunlight, they consume higher amount of carbon dioxide than they release. Moreover, they give out more oxygen than they take in.

          When it is dark, they use oxygen and release carbon dioxide like any other animals and humans.

          This process was first described by the Dutch doctor Jan Ingenhousz in 1779 in his book ‘Experiments Upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and of injuring it in the Shade and at Night.’

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          Smallpox was a deadly viral infection that was common around 200 years ago. The virus spread like wildfire and killed many people.

          The disease didn’t have any cure until Edward Jenner, a British surgeon, found out something strange. Jenner noticed that people who caught a similar but milder disease called cowpox were immune to smallpox. In 1796, he scratched a boy’s skin and applied fluid from a girl with cowpox. The boy later survived deliberate smallpox infection. This was the world’s first vaccine.

          We were all given vaccines during different periods of our life; vaccination against diphtheria, chicken pox, TB and so on. Have you ever wondered why?

          When our bodies are afflicted by certain viruses or foreign entities, it creates different antibodies to destroy the invaders. But serious infections can often overwhelm the system by the time the correct antibodies are produced.

          It was found that advanced warning in the form of harmless vaccines helps to resolve this issue.

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          None of us like to suffer pain. Several home remedies were tried and tested since time immemorial to find substances that would alleviate pain. After a considerable number of trials, a French chemist called Charles Henri Leroux isolated the miracle drug salicylic acid in 1829. This drug could relieve pain and fever. The process of its isolation was later improved by an Italian, Raffaele Miria, in 1838.

          In 1853, Charles Frederic Gerhardt buffered salicylic acid with an extra acetyl group to create acetylsalicylic acid, the true aspirin. However, true aspirin was soon forgotten. Its more recognizable tablet form was created by Felix Hoffmann, a German chemist.

          Gerhardt’s findings were rediscovered by Hoffman who later patented it. He also managed to solve many of the problems associated with earlier preparations. For instance, previously when administered with salicylic acid, patients used to experience severe nausea and vomiting. In the late 19th century, when the pharmaceutical company Bayer realised the potential of aspirin, they bought its patent and began mass production.

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