“I have often endeavoured to view the circulation of the blood in terrestrial animals, but without success, by reason that no parts of their bodies were sufficiently transparent.”

Among other things, I saw in the body of one of these animalcules a bright and round corpuscle, placed near the head, and in which a very wonderful swift motion was to be seen, consisting of an alternate extension and contraction.

[M]y 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.

In it, that sometimes more than a thousand were moving about in an amount of material the size of a grain of sand…

Whenever I found something remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people be informed thereof.

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

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

And I judge that some of these little creatures were above a thousand times smaller than the smallest ones I have ever yet seen, upon the rind of cheese, in wheaten flour, mould, and the like.

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?

The 31th of May, I perceived in the same water more of those Animals, as also some that were somewhat bigger.

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.

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.

There is not in the universe a more ridiculous, nor a more contemptible animal, than a proud clergyman.

What is the Law of the Jungle? Strike first and then give tongue.

We are the storytelling animal.

My great forte in killing buffaloes was to get them circling by riding my horse at the head of the herd and shooting their leaders. Thus the brutes behind were crowded to the left, so that they were soon going round and round.

Thirst teaches all animals to drink, but drunkenness belongs only to man.

Be more than man, or thou’rt less than an ant.

I can say with sincerity that I like cats. A cat is an animal which has more human feelings than almost any other.

Take a cat, nourish it well with milk and tender meat, make it a couch of silk.