“How little do we discover in comparison of those things which now are and forever will be hidden from our sight? The whole of which I am fully persuaded no one will ever be able to dive into, and to explain their causes and effects.”

This particle I concluded to be the heart.

For, the circumference of one of these little Animals in water, is not so big as the thickness of a hair in a Cheese-mite.

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 with the naked eye)

Ten hundred thousand of them could not equal the dimensions of a grain of such course Sand.

I observed certain animalcules, within whole bodies I saw so quick a motion as to exceed belief; they were about the size of a large grain of sand, and their bodies being transparent, that the internal motion could plainly be seen.

I have divers times endeavoured to see and to know, what parts the Blood consists of; and at length I have observ’d, taking some Blood out of my own hand, that it consists of small round globuls driven through a Crystalline humidity or water.

The whole circumference of each of these streaks was about the thickness of a hair of one’s head. … all consisted of very small green globules joined together: and there were very many small green globules as well. [The earliest recorded observation of the common green alga Spyrogyra.]

I saw this vast number of animalcules not all through the semen, but only in the liquid matter adhering to the thicker part.

Examining this water…I found floating therein divers earthy particles, and some green streaks, spirally wound serpent-wise.

My determination is not to remain stubbornly with my ideas, but I’ll leave them and go over to others as soon as I am shown plausible reasons which I can grasp.

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

I’ve never taught one, because if I taught one, I’d have to teach others. I would give myself over to a slavery, whereas I want to stay a free man.

How inscrutable and incomprehensible are the hidden works of Nature!

Just as the supposed number may differ from the true number by fully 100, 150, or even 200 in a flock of 600 sheep, so may I be even more out of my reckoning in the case of these very little animalcules.

Man comes not from an egg but from an animalcule that is found in male sperm.

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

Never compare yourself to anyone, everyone’s life is different, difficulties are different, the path is different.

Political tyranny is nothing compared to the social tyranny and a reformer who defies society is a more courageous man than a politician who defies Government.

Love in action is a harsh and dreadful thing compared with love in dreams.

Comparison will only hinder your progress.

Love is like infinity: You can’t have more or less infinity, and you can’t compare two things to see if they’re “equally infinite.” Infinity just is, and that’s the way I think love is, too.

For today’s generation of blacks to act as if their struggle compares to that of two generations ago insults and diminishes that generation’s struggle.

Minimalism brings freedom from the weight of comparing your life to others.

Never compare yourself to somebody else, because you are so different any unique.