On this date, the Dutch microscopist Antony van Leeuwenhoek was born. He made some of the most important discoveries in the history of biology. During his lifetime, Leeuwenhoek ground over 500 optical lenses and created over 400 different types of microscopes, only nine of which still exist today. Leeuwenhoek was the first person to see bacteria, free-living and parasitic microscopic protists, sperm cells, blood cells, microscopic nematodes and rotifers, and much more. His researches on lower animals refuted the doctrine of spontaneous generation, and his observations helped lay the foundations for microbiology.
It is worth noting that Leeuwenhoek’s early discoveries in the field of microbiology are analogous to Galileo’s early discoveries in the field of astronomy. Both men used the newly improved optical technologies of their day to make major discoveries that entirely overturned traditional beliefs and theories in their respective fields, and both men were initially met with strong skepticism and resistance to the inevitable conclusions to which their discoveries led. Ultimately, Leeuwenhoek was more fortunate than Galileo in that his discoveries were eventually widely accepted and applauded in his lifetime, whereas Galileo’s were not. In addition, Leeuwenhoek’s main opposition was from the scientific community, not the religious community, because Holland was freer of religious persecution than many other European nations at the time. Galileo, for example, faced strong religious persecution.