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

Antonie van Leeuwenhoek

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

Amount Grain Material More Move Sand Size Sometimes Thousand
Man has always to be busy with his thoughts if anything is to be accomplished.
ANTONIE VAN LEEUWENHOEK

Accomplish Always Anything Busy Men
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.
ANTONIE VAN LEEUWENHOEK

Comparison Discover Explanation Forever Hide Myself Ourselves Sight
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.
ANTONIE VAN LEEUWENHOEK

Blood Drive Humidity See Talk Time Water
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.
ANTONIE VAN LEEUWENHOEK

Alternative Among Anmalcule ContrAction Head Moorningm Consist Place Swift Thing
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.
ANTONIE VAN LEEUWENHOEK

Freedom Man Myself Slave Stay Teaching
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)
ANTONIE VAN LEEUWENHOEK

Biggest Cheese Eye Grain Hundred Imagine Move Naked Ordinary Sand Thousand
[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.
ANTONIE VAN LEEUWENHOEK

Chiefly Crave Done Knowledge Men More Praise Pursue Time Work
In the year 1657 I discovered very small living creatures in rain water.
ANTONIE VAN LEEUWENHOEK

Creature Discover Live Rain Water
For my part, I hold it equally impossible for a small shellfish to be produced without generation as for a whale to have its origin from the mud.
ANTONIE VAN LEEUWENHOEK

Equality Hold Myself Origin Production Small
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.
ANTONIE VAN LEEUWENHOEK

Anything Discovery Down Inform might People Put Remarkable
For my part, I would say that the male sperm and seeds of plants have been penetrated so far that there is nothing further to discover in this great secret, but I could err in my opinion.
ANTONIE VAN LEEUWENHOEK

Biology Discover Errors Greatness Myself Opinion Plant Science Secret
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.
ANTONIE VAN LEEUWENHOEK

Big Cheese Circumstance Mite One Thickness 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?
ANTONIE VAN LEEUWENHOEK

Believe Goodness Myself Observation Time Trouble
In the year 1657 I discovered very small living creatures in rain water.
ANTONIE VAN LEEUWENHOEK

Creature Discover Live Rain Small Water Year
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.
ANTONIE VAN LEEUWENHOEK

Animal Difference Myself Number True