my teachers had never told me of him (possibly, I now think,
because they were unable to utter his name). I found that he
was honourably mentioned as a pioneer in many different fields
of scientific research -- his discovery of the Protozoa in infusions
being only one of his many noteworthy achievements. An odd
circumstance, which (I remember) struck me forcibly at the time,
was that this old Hollander -- for some reason unexplained --
apparently made a practice of publishing his observations in
English in our Philosophical Transactions, and was himself
actually a Fellow of our own Royal Societyof London. This
then seemed to me very queer and inexplicable : yet had it not
so happened, the present book would never have been written.

After this my first meeting with Leeuwenhoek, it chanced
that my studies led me away from the protozoa in infusions to
those living inside frogs. I spent two or three painful years in
their pursuit; and in reading up the writings on, the subject, I
found again, to my astonishment, that the earliest observations
on these organisms too had been, made by the same person --
Leeuwenhoekonce more. This revived my interest in him, and
caused me to look into his publications anew. But I made little
progress in my inquiries, because his original records were at that
time inaccessible; and the second-hand sources of information,
then at my disposal were mostly worthless and contradictory --
different authors supplying different references and statements,
most of which turned out to be so incorrect that they led me
nowhere. When I tried to find out something about the man
himself, I met with no better success. Most writers agreed in
calling him "well-known" or even "celebrated", and many
called him "microscopist" or "naturalist" (all excellent epithets,
as I now know). But some people said that he was " a maker
of lenses" and even "the inventor of the microscope" (which
even then I knew to be wrong)., while others said he was a
"physiciav" : and had I then looked further, I should have
found that still others called him "surgeon" and even "Doctor"
and "Professor." Yet all writers seemed to be in agreement on
one point, expressed or implied: and that was that they knew
next to nothing about Leeuwenhoekhimself, despite his alleged
celebrity. No two writers gave the same account of him -- even
when copying one another.

My own next researches (forgive me, dear Reader, for ob-
truding myself in this fashion : it is unfortunately necessary for
the present narrative) were largely concerned with the Bacteria --

-2-