Microorganism are living organisms that are too small to see with the naked eye. They were first observed by Anton van Leeuwenhoek in the 17th century, but he did not make the connection to disease. That had to wait for Pasteur's germ theory of disease 200 years later.
- Wile, Dr. Jay L. Exploring Creation With Biology. Apologia Educational Ministries, Inc. 1998