M]y work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men.
Source: Letter, 12 Jun 1716.
-- Antonie van Leeuwenhoek, (Oct 24 1632-1723), Dutch biologist; He pioneered lens-grinding and microscopy; discovered protozoa; described bacteria, 1683; studied capillary circulation.