History of Microbiology ｜ Contributions of Antony Van Leeuwenhoek ｜ Robert Hooke ｜ Francesco Stellut

Hi friends, welcome to Microbiological Concepts in Tamil. I'm your Dr. Blasi. How are you all? In our last video, we saw a general introduction about microorganisms. Today, we are going to see a discovery about microorganisms. We are going to see how scientists have discovered microorganisms in different periods of time. First, we are going to see Lucretius from 98 to 55 BCE. He was a Roman philosopher. Then, we have Girolamo Fracastero. He was a physician who lived from 1478 to 1553. They say that the disease was caused by invisible living creatures. Then, we have Francisco Stelluti. He lived from 1625 to 1630. He was one of the first to use a microscope to study nature. He used a microscope to study some of the natural bees. Microscopic observations have been made in bees and weevils using a microscope supplied by Galileo. Galileo invented this microscope in 1610. He used Galileo's microscope to study the structure of bees and weevils. Weevils are like beetles. He studied the structure of bees and weevils and drew them on a sheet. He drew what he saw in 1625. Then, we have Robert Hooke. He lived from 1635 to 1703. He was more advanced than him. He invented a compound microscope. The compound microscope has a good lighting system. At the same time, it was one of the best microscopes in his time. The best microscope in his time was the compound microscope invented by Robert Hooke. The lens of the microscope is arranged in tandem. He used two lenses. He arranged the two lenses in front of each other. He could see many objects. But his lens is of poor quality. The lens is not powerful enough to see bacteria. Because of the microscope invented by him, he could not see the cells of bacteria. But he could see something bigger than that. He discovered plant cells. He coined the term cell while discussing the structure of a cork. The cork is a waxy substance in the cell walls. That is called a cork. He coined the term cell while discussing the structure of a cork. Robert Hooke coined the term cell while discussing the structure of a cork. In 1665, he drew a picture of what he saw. He published it in his book called Micrographia. He drew the structure of fungi. He drew the structure of some other plants. He drew the structure of some other organisms. The next person we are going to see is Anthony von Leeuwenhoek. Anthony von Leeuwenhoek is a well known person. He lived from 1632 to 1723. He was the first person to publish his accurate observations of microorganisms. Anthony von Leeuwenhoek was the first person to publish his accurate observations of microorganisms. That is why we call him the father of microbiology. He was not a physician or a scientist. He was a draper and haberdasher. A draper is someone who sells clothes. A haberdasher is someone who sells clothes like buttons, ribbons, zips etc. That is his main job. During his leisure time, he used to construct small microscopes. The microscope that he constructed was composed of double convex glass lenses held between two silver plates. If a light is coming from outside, it will come in many wavelengths. When that light comes from one place to another point, it will divert it to a smaller point. The role of the convex glass lenses is to direct the light to a focal length and bring it to the focus point. The magnification of the microscope that he constructed was 50 to 300 times. He may have eliminated his light specimens by placing them between two pieces of glass and shining light on them at 45 degree angle to the specimen plane. If we want to see a specimen from a microscope, we will need a lens under the microscope. The lens will observe the light and focus it on the specimen. Then we can see the specimen clearly. He used the same method. Both are similar. The light specimen is coming out of two pieces of glass. The light that is coming is rotating at a 45 degree angle. It focuses on the specimen plane. It is helpful for us to visualize the specimen that he is using. Now let us see about the microscope. The mechanism of the microscope is called Microscope Operation Procedure. His microscope is very simple. So the operation procedure is very simple. The specimen is placed on a pin that is manipulated by the means of two screws. The specimen holder has a pin. The specimens are placed on that pin. Two screws are used to adjust the distance between the specimen and the lens. The second screw is used to adjust the height of the specimen. The sample translator screw is located at the bottom of the microscope. It passes through a right angle bracket. A screw is inserted through the right angle bracket. The screw is joined with a metal block. The metal block is located in the middle of the microscope body plates. The specimen holder pin is connected to the other side of the block. When the translator screw is turned, it moves the specimen up or down. The pin that holds the specimen is on the other side of the block. The screw is moving from one side. The holder that holds the sample is on the other side. When the translator screw is turned, the specimen moves up or down. The screw that is perpendicular to the block is used to adjust the height of the specimen and the lens. When the screw is turned, it pushes against the metal plates and moves the specimen toward or away from the lens. The screw is used to adjust the height of the specimen and the lens. The background of the light illumination is darkened to make the bacteria visible. In the beginning of 1673, he wrote a letter to the Royal Society of London. In 1674, he observed protozoa for the first time. He discovered many small creatures called animalcules. He took samples from rain water, pond, well water, human mouth and intestine. He calculated the size of the animalcules. We are looking at the picture with his microscope. In 1677, Stephen Ham, his co-worker, observed spermatozoa from insects, dogs and man. He also studied the structure of optic lens. He studied the fine structure of plants. He studied the development of embryo from an unfertilized egg cell. In 1680, he noticed that yeast consists of minute globular particles. In 1660, he studied the development of blood capillaries. then he continues, first of all he gives a complete description of red blood cells he says that this is how red blood cells look like then his first drawings were published in 1683 in the Royal Society of Philosophical Transactions it was published when we see his description we can see that he has seen both Prokaryotes and Protosovar I will post the continuation of this in the next video If you have any doubts regarding this video, please ask in the comment section I will give you the explanation for that