124 LEEUWENHOEK AND HIS “LITTLE ANIMALS”’ 
These animalcules were of the smallest sort’ that I had 
as yet seen. 
The 12th of June, in the morning (the wind being west, 
with both sunshine and an overcast sky), observing again, 
I saw the foresaid animalcules in such great numbers in 
the water which I took from the surface, that now they 
did not amount to merely one or two thousand in one 
drop. 
The 13th ditto, in the morning, examining the water 
again, I discovered, besides the foresaid animalcules, a 
sort of little animals that were fully eight times as big’ 
as the first; and whereas the small animalcules swam 
gently among one another, and moved after the fashion 
of gnats in the air, these large animalcules had a much 
swifter motion; and as they turned and tumbled all 
around and about, they would make a quick dart.°® 
These animalcules were almost round. * 
On the 14th of June I did perceive the very little 
animalcules in no less number. 
On the 16th ditto, the animalcules seen as before; and 
the water (which had been, in all, about 4 of a pint) 
being now more than half dried up, I flung it away. 
5th Observation. Rain-water. 
The 9th of June,’ I put some of the last-collected 
water, likewise in a clean wine-glass, in my closet; and 
*4.e., probably Monas sp. again. 
? On L.’s system this means “ twice as long”. 
= nmamen deselve een snelle scheut MS. “and then making a sudden 
downfall”? Phil. Trans. L.’s meaning seems clearly to be that given above 
(i.e., they sometimes made sudden shoots or darts forward). Oldenburg 
renders his words as though scheut = Fr. chute. 
4 It seems to me almost certain that the animalcule here described was 
the common ciliate Cyclidiwm. This is the only likely organism—of this 
order of magnitude—which makes sudden springs (hence its name of “ flea- 
animalcule”’). The only objection to this interpretation is the statement 
that it was ‘‘almost round’’: but it must be remembered that L. made 
his observations under a very inadequate magnification. 
> Anno 1676. 
