188 
ce 
LEEUWENHOEK AND HIS LITTLE ANIMALS ”’ 
animalcules are furnished withal; and more especially 
when I have been asked, whether I am able to see the 
particles of water itself? T’o which I did often answer, 
that there be little animals in water that are many 
million times smaller than a sand-grain; and that these 
little animals, on which I can discern no feet, must not- 
withstanding be furnished with instruments for motion ; 
and that these instruments must themselves consist, in 
part, of blood-vessels which convey nourishment into 
them, and of sinews which move them; and that through 
these vessels, moreover, water must also pass. And this 
being so, we must suppose the particles of the water itself 
to be so small as to be, for us, inconceivable: and I’m 
persuaded that no man will ever advance so far in science 
as to be able to gaze upon the particles whereof water 
itself consisteth. 
I shall here first lay down the proportion which the © 
animalcules bear to a sand-grain, in so far as my eye is 
able to arrive at it; together with the number of 
animalcules proportionate to the bigness of a cubic 
inch. 
I usually judge that three or four hundred of the 
smallest animalcules, laid out one against another, 
would reach to the length of the axis of a common grain 
of sand; and taking only the least number (to wit 300), 
then 
27000000 animalcules together are 
as big as a sand-grain. 
Let’s assume that such a sand-grain is so big, that 
80 of them, lying one against the other, would make up 
the length of one inch as BC [Text-fig. 1]. 
