80 BIOLOGY AND ITS MAKERS 
His grandfather and his great-grandfather were Delft brewers, 
and his grandmother a brewer’s daughter. The family were 
doubtless wealthy. His schooling seems to have been brought 
to a close at the age of sixteen, when he was ‘removed to a 
clothing business in Amsterdam, where he filled the office of 
bookkeeper and cashier.” After a few years he returned to 
Delft, and at the age of twenty-two he married, and gave 
himself up largely to studies in natural history. Six years 
after his marriage he obtained the appointment mentioned 
above. He was twice married, but left only one child, a 
daughter by his first wife. In the old church at Delft is a 
monument erected by this daughter to the memory of her 
father. 
He led an easy, prosperous, but withal a busy life. The 
microscope had recently been invented, and for observation 
with that new instrument Leeuwenhoek showed an avidity 
amounting to a passion. 
“That he was in comfortable, if not affluent, circum- 
stances is clear from the character of his writings; that he 
was not troubled by any very anxious and responsible duties 
is certain from the continuity of his scientific work; that he 
could secure the services of persons of influence is discernible 
from the circumstances that, in 1673, De Graaf sent his first 
paper to the Royal Society of London; that in 1680 the same 
society admitted him as fellow; that the directors of the East 
India Company sent him specimens of natural history, and 
that, in 1698, Peter the Great paid him a call to inspect his 
microscopes and their revelations.” 
Leeuwenhoek seems to have been fascinated by the mar- 
vels of the microscopic world, but the extent and quality of 
his work lifted him above the level of the dilettante. He 
was net, like Malpighi and Swammerdam, a skilled dissector, 
but turned his microscope in all directions; to the mineral 
as well as to the vegetable and animal kingdoms. Just when 
