Anton Van Leeuwenhoek Letter

In one letter he described for the first time the characteristic bacteria of the human mouth. He wrote:

I have several gentlewomen in my house, who were keen on seeing the little eels in vinegar; but some of them were so disgusted at the specticle, that they vowed they'd never use vinegar again. But what if one should till such people in the future that there are more animals living in the scum on the teeth in a man's mouth, than there are men in a whole kingdom?

But Leeuwenhoek’s death has ended this observation of microbial world, though everybody has marveled his discoveries. This was primarily because of the lack of skilled professionals for production of high quality simple microscope after Leeuwenhoek as simple microscope of high magnification is very difficult to make. There are compound microscopes available, but they suffer from serious optical defects. This is why ‘Robert Hooke’, a very capable & careful observer of Leeuwenhoek’s time, who was observing the microbial world with his compound microscope, could not see the intricate details seen by Leeuwenhoek simply because of the optical defects of his microscopes. So it took more than a century after Leeuwenhoek’s death (1820) to repeat his experiments with compound microscope after development of optical science. Meanwhile microbiology had also developed in another way i.e. the roles it plays in transformation of matter & causation of disease. Leeuwenhoek is considered the father of microscopy.

References: General Microbiology 5th edition.