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Saturday, October 13, 2018

Antonie van Leeuwenhoek and microscopic life


Photo source: Wikimedia Commons, Jan Verkolje


Antonie van Leeuwenhoek (1632-1723) was a Dutch microbiologist best known for his contributions to microscopy and the discovery of many microscopic organisms. Antiquarian Martin Folkes said,


"We have seen so many, and those of [Leeuwenhoek's] most surprising discoveries, so perfectly confirmed by great numbers of the most curious and judicious observers, that there can surely be no reason to distrust his accuracy in those others which have not yet been so frequently or carefully examined." (Account of Mr. Leeuwenhoek's Microscopes, 1723)


The rest of this post is some quotes from Leeuwenhoek.


Microscopic life


"...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." (Letter to the Royal Society, 1674)


"...we see little living animals and see their legs and must judge the same to be ten thousand times thinner than a hair of my beard, and when I see animals living that are more than a hundred times smaller and am unable to observe any legs at all, I still conclude from their structure and movements of their bodies that they do have legs." (Letter to N. Grew, 1678)


"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. 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. This particle I concluded to be the heart." (


"If we reflect that a small creature such as this is provided, not only with external members, but also with intestines and other organs, we have no reason to doubt that a like creature, even if a thousand million times smaller, may already be provided with all its external and internal organs... though they may be hidden from our eyes." (Letter to the Royal Society, 1685)


Is reality infinitely microscopic?


"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." (


"How inscrutable and incomprehensible are the hidden works of Nature!" (