part of a letter from Mr Antony van Leeuwenhoek to the Royal Society of London
On the 30th day of August, 1700,
I ordered water to be drawn from the ditches
where the wormy sheep drank
& when I came home, & was busy viewing
the multiplicity of very small animals
drifting through the water, I saw
very many great round particles
of the bigness of a corn of sand
moving & revolving in the water.
Their outward skin was quite set over
with protruberant parts, which seemed
triangular & pointed towards the end,
all orderly & equally distant,
so that on one small body did stand
about two thousand. This was to me
a very pleasant sight, because as often
as I looked they never lay still
& in all their motion never ceased to turn.
I fancied at first that they were small
green animals. The smaller they were,
the deeper green their colour,
but the largest, those as big as
a great corn of sand, had turned clear,
though each enclosed 5, 6
or 7 — nay, some to 12
small globules, of the same shape
as the body that held them.
I thought it strange that in all the turning
of the first globe, the globules within
did not change their places in the least
& never came to touch.
Then the largest & clearest of all
began to open before my eyes,
& one of the round particles within, of
a delicate green, slipped out & began
to move in the water on its own,
as had the one it issued from —
which now ceased all motion.
Within a small time after,
a second & third also
slipped out, one after the other,
& so by degrees they all emerged.
After some time, the original particle
united again with the water,
for I could perceive no sign of it.
Most who would see these particles
move in the water would swear
they were live creatures, especially
the way they tumbled about
from one side to another.
But in three days time,
that great crowd of round particles
& all the living creatures
in the glass were gone.