IV. An Extract of a Letter from Mr. Anth. 
Van Leuwenhoek, Concerning Animalcules 
found on the Teeth } of the Scaleynefl of the 
Skin^ Sec. 
I Have often endeavoured to difcover Animalcules in 
Spittle, but in vain : But examining a kind of gritty 
Matter from between my Teeth, and mixing it Tbme- 
times with Rain-water, and fometimes with Spittle, both 
which before had no Animalcules, I difcovered therein 
with admiration a great number of very (mall ones 
moving the greateft whereof are reprefented Fig. 2. 
A, they had a very ftrong and (wift Motion in the Wa- 
ter like Eeles, of thefe larger there were not many : 
A fecond fort is reprefented by B. thefe oft turned them- 
felves round like a Top, and moved fometimes as is 
fhewn by the Line C. B. thefe were much more in num- 
ber. The Figure of the third fort I could not well dif- 
cover, fometimes theyappeared oval, and at other times 
round, they were fo fmall that I could not difcern them 
greater than as at E. they moved fwiftly by each other 
like Gnats playing in the Air, and of thefe I difcerned 
Thoufands in a drop v of Water they fliewed no bigger 
than a Sand, and in the Drop, the Water was to the Ani- 
malcules as 9 to i. But moil of the Matter I exami- 
ned, confided of long (lender parts all of a thicknefs, but 
differing in length as at E and one crooked one amongft 
the reft ; and becaufe I have forni$rly obferved Ani- 
malcules of this fliape in Water, I endeavoured to dif- 
cover if thefe lived but could not. I have found the 
fame in the Matter taken from between the Teeth of 
other 
