Animalcules
Journal:
Encyclopaedia londinensis
Volume:
I, no. 45, p. 717
Publisher:
London: J. Adlard
Year:
1810
Encyclopaedia londinensis, or, Universal dictionary of arts, sciences, and literature
This 10-page entry discusses what was known at the time, dividing them into animalcules that had no external organs and those that do have external organs.
Mentions Leeuwenhoek several times.