My Science School

          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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          Though Robert Hooke coined the term ‘cell’, Theodor Schwann and Matthias Jakob Schleiden are accredited with the first cell theory for their work in the 1830s.

          The cell theory states that living things are composed of cells, be it unicellular or multicellular; cells are the basic unit of life and cells arise from existing cells. Although Schleiden and Schwann proposed that cells arise through spontaneous generation, this was proven wrong.

The accepted tenets of modern cell theory are as follows:

1. Cells are the fundamental units of structure and function in all living things.

2. All organisms are made up of one or more cells.

3. Cells arise from pre-existing cells through cellular division.

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        In the year 1859, Charles Darwin, a doctor’s son, shook the world with the publication of a book. The book, titled, On the Origin of Species, claimed with supporting evidence that plants and animals evolved from earlier forms and are still evolving. Darwin’s work opposed the belief that animals and plants were created as we see them today.

          His theory of evolution is based on the idea of natural selection. Though the members of a species have many similarities, each one is slightly different from the other. The differences that some members possess help them survive by competing with the others. And the traits that helped them survive are passed on to their offspring.

          Darwin observed the differences between the finches on various Pacific Islands and studied fossil records. The concept of natural selection came to him after reading an essay by Thomas Malthus in which Malthus said that animals compete to survive. Darwin realised that such a competition can explain the evolution of animals.

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          In the olden days, surgeries and other medical treatments were conducted without administering pain killers. The patient had to suffer severe pain to get the treatment done. Surgeons and doctors worked to discover sedatives that would numb the patient’s body, so that the surgery would be painless, or rather less painful.

          Two American dentists, Horace Wells and William Morton were the first to use anaesthetics. Wells made an unsuccessful attempt to use laughing gas (nitrous oxide) in 1845 in addition to trying if ether would act as a local anaesthetic. Morton tried making his patients inhale ether and successfully demonstrated anaesthetic surgery in 1846.

          Next year, a Scottish surgeon James Simpson started using chloroform to help women through the pain of childbirth. He attained immense popularity after giving chloroform to Queen Victoria during the birth of Prince Leopold, her eighth child.

         Much safer and effective alternatives to sulphuric ether and chloroform are available today. Mainly sevoflurane and isoflurane are used as anaesthetics. General anaesthesia is considered as one of the greatest discoveries of all time.

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          The work of ancient Greek physician Galen formed the basis of what doctors knew about human anatomy for centuries. However, Andreas Vesalius, a 16th century Flemish physician, approached the structure of the human body from a fresh perspective.

          Until then, dissection of human bodies was not used in the study of human anatomy; most of Galen’s studies were based on dissection of animals. Unlike his predecessors, Vesalius dissected human bodies and conducted his studies through direct observation.

          His discoveries were recorded and published in 1543 titled De Humani Corporis Fabrica, his masterpiece. This work revolutionized medical science and laid the foundation for research on modern human anatomy. Consequently, Vesalius came to be considered as the founder of studies on modern human anatomy.

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          During the mid-19th century, humans had still not discovered the science behind some natural processes. For instance, what turned grape into wine? And why did it acquire a sour taste?

          A French chemist, Louis Pasteur, found that microorganisms are responsible for this. He also proved that, rather than polluted air, diseases were transmitted by these invisible organisms. Before Pasteur, invasion by invisible organisms were thought to be responsible for decay and disease.

         In 1864, the French Academy of Sciences officially accepted Pasteur’s conclusions. Three years later he was provided with his own laboratory in France’s Ecole Superieure, a graduate school in Paris. Pasteur’s ‘germ’ theory soon received wider acceptance. He revolutionized medicine and the food industry by establishing the reality of germs. He also developed the earliest vaccines against fowl cholera, anthrax, and rabies. Pasteur became a household name after he invented the technique for treating milk and wine to prevent bacterial contamination. This process is now called pasteurization.

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          A Hungarian doctor named lgnaz Semmelweis once asked the medical students at Vienna’s maternity hospital to disinfect their hands. He had proved that this made their presence in labour rooms less dangerous. But this offended his superiors and he was dismissed from service. This happened in 1849.

          The indifferent attitude towards disinfecting continued well after 1864 when Louis Pasteur’s germ theory was accepted in France. Most surgeons continued operating without even changing into clean clothes.

          However, things began to change in 1867 when Joseph Lister published the paper “Antiseptic Principle of the Practice of Surgery”. Lister was inspired by Louis Pasteur’s germ theory of putrefaction. He advocated the use of carbolic acid, which is a powerful germ killer to disinfect. He had already begun putting this into practice in his operating theatres and on to dressings by 1865. Lister’s introduction of antiseptic surgical methods paved the way for modern sterile surgery.

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         “You look exactly like your mother!” “Like father like son.” Most of us might have heard comments like these. It is true that we resemble our parents. But why is it so? Because we inherit certain traits from them.

          The fundamental laws of inheritance were discovered by Gregor Mendel. Through his work on pea plants, he deduced that genes come in pairs and are inherited as distinct units, one from each parent. For example, a man and a woman both with brown eyes could have a one-in-four chance of producing a child with blue eyes. Mendel published his discoveries in 1865 after spending eight years doing genetic experiments on pea plants. However, his work was disregarded by a vast majority.

          It was Dutch botanist Hugo De Vries who realised the importance of Mendel’s discoveries in 1900. Many rules of heredity were established by Mendel’s experiments and are now referred to as the laws of Mendelian inheritance. He gained recognition as the founder of the modern science of genetics posthumously.

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          There is a lot of confusion as to who actually discovered DNA. Though many give credit to James Watson and Francis Crick for discovering DNA in the 1950s, the actual discovery occurred decades before that.

          Watson and Crick came to their monumental conclusion about the structure of DNA in 1953 by building up on the work of pioneers before them.

          The molecule now known as DNA was first identified in the 1860s by the Swiss chemist, Johann Friedrich Miescher who called it ‘nuclein’.

          Although the significance of this discovery was not initially recognised, it set further research and discoveries in motion. In the 1880s, Albrecht Kossel isolated the five organic compounds that are present in nucleic acid: adenine, cytosine, guanine, thymine and uracil. The role of DNA in heredity was confirmed in 1952, when Alfred Hershey and Martha Chase showed through experiments that DNA is genetic material.

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          Fingerprints have been found on ancient Babylonian clay tablets. They are excellent in establishing the identity of individuals and hence widely used to track down criminals. However, this is only possible because they have been systematically classified, making it easy to compare new prints with the ones on record.

          British scientist Francis Galton devised a basic classification after confirming that every fingerprint is different. Galton estimated that there is only 1 in 64 billion chance of a false positive, which happens if two individuals have the same fingerprint. An Argentine police officer named Juan Vucetich created the method of recording the fingerprints of individuals on file by studying Galton’s pattern types. He set up the world’s first fingerprint bureau in 1892.

          A fingerprint bureau was established in Kolkata in 1897. Azizul Haque and Hem Chandra Bose were the two fingerprint experts in Kolkata. They co-devised a system that became popular. It was named the Henry Classification System, after their supervisor Edward Henry.

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          When people recover from bacterial illnesses, they often develop antitoxins that give them immunity against recurrence of the disease. An antitoxin is an antibody with the ability to neutralize a specific toxin.

          One of the most popular antitoxins is the diphtheria antitoxin. In 1888, Emile Roux and Alexandre Yersin showed that the toxins produced by the Corynebacterium diphtheriae causes symptoms of diphtheria in animals. Two years later, the first antitoxin to diphtheria was made when Shibasaburo Kitasato and Emil von Behring immunised guinea pigs with heat-treated diphtheria toxin. Behring received the Nobel Prize for Physiology or Medicine in 1901.

          It is believed that the diphtheria antitoxin was first used to treat a diseased human in 1891. Today antitoxins are used in the treatment of botulism, diphtheria, dysentery, gas gangrene and tetanus.

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          Russian microbiologist Dmitry Ivanovsky was the first to realize that bacteria were not the only infective agent. Ivanovsky published a paper on a virus infection of tobacco plants in 1892. However, lvanovsky probably did not grasp the full meaning of his discovery. Martinus W. Beijerinck, in 1898 became the first one to use the term ‘virus’ to indicate the microorganism causing tobacco mosaic disease.

          A virus is an infectious particle that can multiply only inside a living cell. Since it is made of only a set of genes wrapped in protective covering, a virus takes over a plant or animal cell and forces it to replicate the invader. Both lvanovsky and Beijerinck discovered that viruses were smaller than bacteria and invisible under an ordinary microscope. These two scientists brought significant and complementary contributions to the discovery of viruses. The discovery of tobacco mosaic virus stands out as a milestone in the history of virology.

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          Many aspects of the human body remained unclear to us till the advancement of medical science. The reason why certain blood transfusions were successful while others could be deadly was discovered only in 1900 by Karl Landsteiner at the University of Vienna. He discovered the ABO blood group system by mixing the red cells and serum of each of his staff. Landsteiner demonstrated that serum of some people agglutinated or caused clumping of red blood cells of others.

          From these early experiments, he identified three blood groups which he called A, B, and C. The last one was later renamed ‘O’ from the German term ‘Ohne’ which means ‘without’, similar to ‘zero’ or ‘null’ in English.

          The fourth blood group AB, which is rarer than the others, was discovered a year later. Landsteiner was awarded the Nobel Prize in Physiology or Medicine in 1930 for his work.

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