“The 4th sort of creatures... which moved through the 3 former sorts, were incredibly small, and so small in my eye that I judged, that if 100 of them lay [stretched out] one by another, they would not equal the length of a grain of course Sand; and according to this estimate, ten hundred thousand of them could not equal the dimensions of a grain of such course Sand. There was discover'd by me a fifth sort, which had near the thickness of the former, but they were almost twice as long. The first time bacteria were observed.”
![“The 4th sort of creatures... which moved through the 3 former sorts, were incredibly small, and so small in my eye that I judged, that if 100 of them lay [stretched out] one by another, they would not equal the length of a grain of course Sand; and according to this estimate, ten hundred thousand…” quote by Antonie van Leeuwenhoek](https://sms4smile.com/quotes/img-quotes/9f1/antonie-van-leeuwenhoek-17943_bacteria_the-4th-sort-of-creatures-which-moved-th_627470.jpg)
![“The 31th of May, I perceived in the same water more of those Animals, as also some that were somewhat bigger. And I imagine, that [ten hundred thousand] of these little Creatures do not equal an ordinary grain of Sand in bigness: And comparing them with a Cheese-mite (which may be seen to move…” quote by Antonie van Leeuwenhoek](https://sms4smile.com/quotes/img-quotes/a1e/antonie-van-leeuwenhoek-17943_animal_the-31th-of-may-i-perceived-in-the-same_2552391.jpg)
![“I've spent more time than many will believe [making microscopic observations], but I've done them with joy, and I've taken no notice those who have said why take so much trouble and what good is it?” quote by Antonie van Leeuwenhoek](https://sms4smile.com/quotes/img-quotes/5b8/antonie-van-leeuwenhoek-17943_believe_i-ve-spent-more-time-than-many-will-beli_560375.jpg)
