My work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men.
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
A man has always to be busy with his thoughts if anything is to be accomplished.
Whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.
In the year of 1657 I discovered very small living creatures in rain water.