Antonie van Leeuwenhoek

I have often thought that if I had not been so accurate in my measurements, my conclusions would have been flawed.

I have often thought that if I had not been so honest in reporting my findings, I would not have gained the trust of my peers.

I have often thought that if I had not been so humble in my approach, I would not have been receptive to new knowledge.

I have often thought that if I had not been so independent in my thinking, I would not have challenged prevailing beliefs.

I have often thought that if I had not been so dedicated to the pursuit of truth, I would not have devoted my life to science.

I have often thought that if I had not been so passionate about sharing my discoveries, I would not have written so many letters.

I have often thought that if I had not been so determined to leave a legacy, my work might have been forgotten.

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 write down my discovery, so that all ingenious people might be informed thereof.

I have often been told that I am too curious, and that I should not waste my time on such trifles. But I believe that there is no knowledge that is not worth pursuing.

I have been at great pains to make my observations as accurate as possible, and I have spared no expense in procuring the best instruments.

I have seen with my own eyes, what no man has seen before.

My method of observing is so simple, that it is a wonder that no one has thought of it before.

I have discovered living creatures in water, smaller than any that have ever been seen by the eye of man.

These animalcules are so exceedingly small, that I cannot but believe that there are many thousands of them in a single drop of water.

I have observed the blood of various animals, and I have found that it consists of an incredible number of small globules.

I have seen the circulation of the blood in the capillaries of a frog's foot, which is a most wonderful sight.

I have also observed the structure of muscle fibers, and I have found that they are composed of many smaller fibers.

I have examined the structure of teeth, and I have found that they are full of small tubes.

I have discovered that yeast consists of living organisms, which are responsible for fermentation.

I have observed bacteria in various substances, including plaque from my own teeth.