Scientific Pursuit

In 1654, Leeuwenhoek came back to Delft, bought a house and set up business as a draper. He remained at Delft for the rest of his life. In 1660, he was appointed chamberlain to the sheriffs of Delft, a position that he retained for the next 39 years. It is probable that his scientific pursuits began during this time because there is evidence that he took one of his microscopes with him on a visit to England and studied chalk from the cliff of Kent. He probably took to grinding lenses for making simple microscopes as a hobby, which later turned into a passion.

In 1673, Leeuwenhoek's work was brought to the notice of the Royal Society by Regnier de Graaf, a brilliant young physician and the Society requested further communication from him on this matter. Thus began a long period of correspondence between Leeuwenhoek and the Royal Society that lasted until the formers death. He described all his microscopic observations in letters (numbering nearly 300) written in Dutch. Although he never wrote a book or scientific paper, these letters were large enough and factual enough to be considered as scientifically valid and it is easy to identify easily many of the organisms he studied from the detailed descriptions given in the letters.

In 1677, Robert Hooke built microscopes according to Leeuwenhoek's specifications and confirmed the Dutchman's observations. Three years later, the Royal Society honoured him by electing him as a Fellow, but though this pleased him a great deal, Leeuwenhoek never found the time to visit London to sign the register. By now Leeuwenhoek had become famous and many important people came to visit him including the Queen of England, Frederick I of Prussia and Peter the Great, Tsar of Russia (who came incognito). In 1683,he made probably his greatest discovery -bacteria. No one else was to detect bacteria for more than a century. Leeuwenhoek continued with his passion for observation and description well into his last years. He was little interested in anything else but in his chosen field he was unrivalled.

He died on August 26, 1723, leaving behind his sole surviving child Maria, who had devotedly cared for him in his old age. The Microscopes Leeuwenhoek started making as a hobby in his spare time, but with more and more observations, it grew into an obsession. Properly speaking, the instruments were not microscopes at all but simple magnifying glasses. Each consisted of a single biconvex lens of remarkable clarity, which was mounted between two plates. The lens was fixed, and the specimen was raised, lowered or rotated upon its axis by a coarse-threaded screw.

Leeuwenhoek himself ground and polished the lens to exceptional optical quality, having magnifying powers ranging from 50 to 200. The short focal length of the lens (about 1mm) necessitated placing the eye almost in contact with the lens and it is not exactly known how Leeuwenhoek managed to obtain the necessary illumination to achieve his remarkable observations. Some scientists suggest that Leeuwenhoek may have used the optical properties of spherical drops of fluid containing the objects under observation. The Observations Once Leeuwenhoek's passion for observation had been aroused his curiosity was insatiable and he examined whatever he could lay his hands on, including tooth scrapings and ditch water.

He sampled about 200 biological species and mineral objects and even attempted to observe the explosion of gunpowder. Leeuwenhoek first discovered the one-celled animals now called protozoa and opened up a whole new world of microscopic living organisms, too small to be seen by the naked eye. He examined the human capillaries and red blood cells with more care and detail than the original discoverers Malpighi and Swammerdam. In 1682, he clearly described the nucleus within the red blood cells of fish, and the next year noted the sedimentation of erythrocytes from suspension and their lysis upon additions of water. Later on he also discovered the lymphatic capillaries. In 1677, Leeuwenhoek discovered spermatozoa in fresh Semen, gave first time descriptions of the common green algae - Spirogyra and observed several minute organisms such as Vorticell, Monas, Bodo Caudatus and Colpidium which were probably free living protozoa. Leeuwenhoek's most remarkable discovery was probably bacteria, which just about made it to the limit of what his lens could detect. He discovered the Spirochaeta in a sample of his feces, detected five different kinds of bacteria present in his mouth and later discovered some more free living protozoa such as Volvox, Hydra and rotifers.

Anton van Leeuwenhoek is a Dutch Scientist. He is considered the father of microscopy. He was born in Delft, Holland on October 24, 1632 and he lived there for his whole life. The education that he had was little or completely nothing. Leeuwenhoek's areas of study were Life Science and Microbiology. Leeuwenhoek invented the microscope which became a powerful aid in science. Making the microscope was just a hobby of his and after wards, he gave up his business as a manager of a little shop, he started to get into his hobby so he devoted most of his time making the lenses. His lenses where no bigger than a pea. People where amazed of the size of the lenses. He made the microscope by double-convex lenses, which he mounted to a brass plate. When it is held close to his eyes, he could see the objects that were mounted on a pinhead. He studied the tiny objects that he found when he was looking through the microscope. He observed that there were tiny objects, which soon became known as cells.

Anton Van Leeuwenhoek did not invent the microscope but some people still refer to him as the father of microscopy. This is because, his insatiable curiosity coupled with extraordinary skills and stunning discoveries did more to dramatize and popularize the field, than anything else had done before. Leeuwenhoek's discovery of microorganisms has tended to overshadow his other work, which was no less noteworthy. He was one of the first comparative anatomists as he studied the structure of several different species. He was also a pioneer micro-dissectionist and some of his observations are startling even by modern standards. One of his greatest discoveries was parthenogenesis in aphids.

It is remarkable that a man of such humble origins and occupation like Leeuwenhoek could make such a tremendous contribution to the world of science.Indeed, the fact that he continued his fairly comfortable drapery business till the end of his life, yet at the same time found time to build hundreds of microscopes and make startling discoveries speak volumes about his obsession for making observations and his spirit of scientific enquiry.

In his typically modest way, he realized how rare his talents were and that all men were not motivated in the same way as he was.

In a 1715 letter, he noted - "some men go to make money out of science or to get a reputation in the learned world. But in lens grinding and discovering things hidden from our sight these count for naught ……. And over and above all most men are not curious to know: nay some even makes no bones about saying, what does it matter whether we know this or not?"

Throughout his life Leeuwenhoek worked alone and since he could read only Dutch, he could see the illustrations but could not read the writings of the great contemporary microscopists such as Hooke and Malpighi. He continued with his passion for making lenses and observations almost to the end of his long life of 90 years, always cared for by his devoted daughter Maria.

In accordance with his will, 26 of his microscopes were sent to the Royal Society to help scientists carry forward his magnificent work.