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.

A man has always to be busy with his thoughts if anything is to be accomplished.

In the year of 1657 I discovered very small living creatures in rain water.

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?

Please bear in mind that my observations and thoughts are the outcome of my own unaided impulse and curiosity alone; for, besides myself, in our town there be no philosophers who practice this art, so pray, take not amiss my poor pen and the liberty I here take in setting down my random notions.

People who look for the first time through a microscope say, 'Now I see this, and then I see that,' and even a skilled observer can be fooled. On these observations I have spent more time than many will believe, but I have done them with joy, and I have taken no notice of those who have said, 'Why take so much trouble,' and, 'What good is it?'