IV. An extract of a letter from Mr. Anth. Van Leuwenhoek, concerning animalcules found on the teeth; of the scaleyness of the skin, &c

Abstract

I Have often endeavoured to discover Animalcules in Spittle, but in vain: But examining a kind of gritty Matter from between my Teeth, and mixing it sometimes with Rain-water, and sometimes with Spittle, both which before had no Animalcules, I discovered therein with admiration a great number of very small ones moving.