Antonie van Leeuwenhoek

“A man has always to be busy with his thoughts if anything is to be accomplished.”

“We will admit that, out of the mud or sand which is found on the seashore or the beds of our rivers, at low water, shellfish or testaceous animals come forth, but it does not from thence by...”

“I have oft-times been besought, by divers gentlemen, to set down on paper what I have beheld through my newly invented microscopia, but I have generally declined.”

“Life lives on life - it is cruel, but it is God's will. And it is for our good, of course, because if there weren't little animals to eat up the young mussels, our canals would be choked by...”

“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.”

“In rain water, I observed a small red worm and two other kinds of very minute insects; of those of the larger size, I judged that 30,000 together would not equal a coarse sand.”

“I have lately examined water, in which beaten pepper was steeped, and found two sorts of animals for shape, and each of those sorts to contain greater and smaller kinds: the greater I suppos...”

“If any person examines by the microscope that part towards the extremity of the spider's body from whence its thread proceeds, he will observe the spot to be, as it were, surrounded by five...”

“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.”

“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.”

“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.”

“How inscrutable and incomprehensible are the hidden works of Nature!”

“When I have supped too heavily of an evening, I drink in the morning a large number of cups of coffee, and that as hot as I can drink it, so that the sweat breaks out on me, and if by so doi...”

“People who look for the first time through a microscope say, 'Now I see this, and then I see that,' and even a skilled observer can be fooled. On these observations I have spent more time th...”

“Please bear in mind that my observations and thoughts are the outcome of my own unaided impulse and curiosity alone; for, besides myself, in our town there be no philosophers who practice th...”

“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.”

“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...”

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

“I now found that the spider cannot fix its thread to anything without imprinting the hind part of its body on the place, by which pressure it emits an incredible number of excessively small...”

“No one can pretend to say that a fish is ever killed by heat, for many kinds of fish, in the middle of summer, and in the burning heat of the sun, do either play, as it were, on the surface...”