170 
LEEUWENHOEK AND HIS “ LITTLE ANIMALS ”’ 
of water as big as a millet-seed, more than 1000 living 
creatures. This same Gentleman beheld this sight with 
ereat wonder, and all the more because I told him that 
in this very water there were yet 2 or 3 sorts of even 
much smaller creatures that were not revealed to his 
eyes, but which I could see by means of other glasses 
and a different method (which I keep for myself alone). 
Now supposing that this Gentleman really saw 1000 
animalcules in a particle of water but soth of the bigness 
of a millet-seed, that would be 30000 living 
Shoe creatures in a quantity of water as big as a 
9730000 +4+%millet-seed, and consequently 2730000 living 
creatures in one drop of water. Otherwise, I 
imagine the quantity of water to be of the bigness of a 
coarse sand-grain; and in this quantity I imagine that 
I see upwards of 1000 living creatures. Now I take it 
that the bigness of a coarse grain of sand beareth the 
following proportion to a drop of water: If the diameter 
of a sand-grain be 1, then that of a drop of water is more 
than 10, and consequently a drop of water is more than 
1000 times bigger than a sand-erain. ‘Thus there are 
more than a thousand times a thousand living creatures 
in a drop of water. Tis in such a fashion that I make 
my uncertain and imaginary reckoning of the animalcules 
in water: but I guard myself, so far as ‘tis possible, 
against making the number too big, as you can see from 
the foregoing lines of my letter, wherein I have made 
the number not half so big as others well might do. 
My counting is always as uncertain as that of folks 
who, when they see a big flock of sheep being driven, 
say, by merely casting their eye upon them, how many 
sheep there be in the whole flock. In order to do this 
with the greatest exactness, you have to imagine that the 
sheep are running alongside one another, so that the flock 
has a breadth of a certain number: then you multiply 
this by the number which you likewise imagine to make 
up the length, and so you estimate the size of the whole 
