I've spent more time than many will believe [making microscopic observations], but I've done them with joy, and I've taken no notice those who have said why take so much trouble and what good is it?
Source: In Isaac Asimov's Book of Science and Nature Quotations, by Jason Shulman & Isaac Asimov, 1988.
-- Antonie van Leeuwenhoek, (Oct 24 1632-1723), Dutch biologist; He pioneered lens-grinding and microscopy; discovered protozoa; described bacteria, 1683; studied capillary circulation.