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LEEUWENHOEK AND HIS “ LITTLE ANIMALS ”’ 
to lie dry, I threw the latter away, after first of all tasting 
it on my tongue, and finding it as strong as if it had just 
been pounded. 
4th Observation {on Pepper-water |. 
The 14th of June, a certain quantity of whole pepper 
put in well-water. 
The 16th dzttv, in the morning, on examining the same, 
I discovered, in a tiny drop of water, incredibly many 
very little animalcules, and these of divers sorts and sizes.’ 
My further observations I have not made note of, save 
that on the 17th of July still more animalcules were seen, 
and among them many of the little oval creatures” many 
times mentioned already. 
Examining the water again on July 20th, I now saw, 
with very great wonder, that some very long and very 
thin particles (which I imagine had come to my notice 
in various waters before) were alive. These most 
wonderful living creatures seemed, when viewed through 
my microscope, thinner than a very fine hair of one’s 
head, and about as long as the back of a bread-knife,° 
others quite twice as long. Their whole body appeared 
of one and the same thickness throughout, without my 
being able to make out a head or any bodily parts; and 
therewithal their body was very clear, and ’twas thus 
very troublesome to succeed in seeing ’em alive in the 
water. They moved with bendings, as an eel swims in 
the water; only with this difference, that whereas an eel 
always swims with its head in front, and never tail first, 
Bacteria—various sorts. 
Colpidiwm. 
Another of L.’s homely similes. He means that the “animalcules” 
were very long, and uniformly thin—their proportions being similar to those 
of the blunt edge, or back, of a large knife such as is used for cutting bread ; 
though their thickness actually appeared not so great, but even less than 
that of a human hair as seen by the naked eye. Itis a peculiar comparison, 
but on the whole conveys a tolerably accurate notion of the appearance of 
the long thread-bacteria which he was evidently observing. 
