Antonie van Leeuwenhoek

The number of these animals in the scurf of a man's teeth are so many that I believe they exceed the number of men in a kingdom.

From these observations, we discern the great perfection of the infinitely small creatures of God.

I have been for a long time of the opinion that a man's own observation is the best and most certain proof he can have.

I have oft-times examined the blood of different sorts of animals, and have found it to consist of small round globules.

In the structure of a louse, I have observed such exquisite workmanship as seems to surpass all human art.

The discoveries we make with our microscopes are as nothing compared with the vastness of creation.

I did not mind my labour, because I had a great desire to learn the true structure of things.

Nature is nowhere accustomed more openly to display her secret mysteries than in cases where she shows traces of her workings apart from the beaten path.

I have seen with wonder and delight the circulation of the blood in the tail of a small eel.

All these observations... convince me that these little animals are generated from seeds or eggs, and not from putrefaction or spontaneous generation.

I am well aware that these my writings will not be accepted by some, but I am satisfied that they will be of use to those who love the truth.

The parts of a cheese-mite are so small that it is a marvel how they can be put together.

I have spent more time than many will believe in making observations, but I have done so with pleasure, and have taken no notice of those who have said why take so much trouble and what good is it?

In all these investigations I have sought to know the truth, and not to support preconceived opinions.

The wonders of God's creation are infinite, and the smaller the creature, the more astonishing its design.

I observed that the vinegar eels... were in such perpetual motion that they seemed to be a knot of writhing serpents.

By this means [the microscope] I have discovered a new world, which was hitherto unknown to mankind.

It is a common failing of men to think that what they do not understand has no existence.

The eye of a fly is much more perfect than I had imagined, being composed of thousands of little lenses.

I have often examined the sting of a bee, and it is a masterpiece of mechanical contrivance.