Antonie van Leeuwenhoek

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. And therewithal, 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.

I have often seen, with great wonder, that in a very small quantity of water, which had been standing for a few days, there were living creatures, very small, and of various kinds, moving about in a most amusing fashion.

I have had several gentlewomen in my house, who were keen on seeing the little creatures, but some of them were so affrighted at the sight of these little animals, that they durst not look upon them, believing that there were spirits in them.

I have discovered living creatures in water, rain, and snow, in the mouth and intestines of man, and in many other places.

My method for seeing the smallest things is not to be communicated to others, for I do not wish to be robbed of my discoveries.

I have made a discovery that is more wonderful than any I have ever made before, and that is, that there are living creatures in the semen of man.

I have often observed, with great pleasure, that the blood of a healthy man is full of an incredible number of very small, round, red globules, which are so numerous that they touch each other.

I have seen, with great wonder, that the smallest insects have a perfect organization, and that they are as perfectly formed as the largest animals.

I have often observed, with great pleasure, that the smallest creatures have a perfect organization, and that they are as perfectly formed as the largest animals.

We cannot in any better manner glorify the Lord and Creator of the universe than that in all things, how small soever they appear to our naked eyes, but which have yet received the gift of life and power of increase, we contemplate with unmixed admiration his inconceivable power and perfections.

My work often leads to low spirits; a kind of despondency and despair almost like that of the insane.

I have always highly valued the microscope.

In the year 1675 I made several microscopes.

The motion of the animalcules was so swift that I could hardly follow them with my eyes.

I have contrived certain microscopes by which I have increased the power of sight a thousand times.

These little animalcules are so small that a million of them would not equal the size of a coarse grain of sand.

I have observed that in the plaque between the teeth, there are innumerable small animals.

The sperm of a man is a living creature.

Nature does not proceed by leaps and bounds.

I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore.