ce 
52 LEEUWENHOEK AND HIS “ LITTLE ANIMALS” 
observations on chalk are, so far as I have yet ascertained, the 
earliest dated microscopic investigations recorded by Leeuwen- 
hoek: and they dispose of a recent suggestion * that he began 
his career as a microscopist under the influence of his second 
wife—the “ blue-stocking’”’ Cornelia Zwalmius. He did not 
marry this supposedly learned lady ° until 1671; but the fore- 
going extract shows that he was already engaged in making 
microscopic observations at least three years earlier, and when 
we remember that he made all his microscopes and lenses with 
his own hands it seems certain that he must have begun his 
studies whilst his first wife was still alive.’ 
By the end of the XVII Century, when he had been 
demonstrating the scientific possibilities of the microscope 
for more than 25 years, Leeuwenhoek was actually the 
only earnest microscopist in the whole world. It is a 
remarkable fact that in all his later life he had no rivals 
and hardly a single imitator. His observations excited 
the greatest interest—but that was all. Nobody seriously 
attempted to repeat or extend them. ‘The superexcellence 
of his lenses, combined with the exceptional keenness of 
his eye, killed all competition. As early as 1692, Robert 
Hooke, discoursing on “the Fate of Microscopes”’,’ says 
that they “‘are now reduced almost to a single Votary, 
which is Mr. Leewwenhoek; besides whom, I hear of none that 
make any other Use of that Instrument, but for Diversion and 
Pastime”’:’ and he adds later that the microscope at that 
* Schierbeek (1929). 
* The only evidence that Cornelia was a highly-educated female appears 
to be (1) that her father was a clergyman; (2) that her brother was a 
doctor; and (3) that she once signed her name “ Swalmia” (instead of 
Swalmius) on a legal document—which has been taken to prove that she 
knew Latin. There is no evidence, however, to show that she changed the 
gender of her patronymic on her own initiative: and it seems to me unlikely 
that women were less dependent on their male relatives and friends 250 
years ago than they are today. 
° It is not known with certainty when L. began making “ microscopes.”’ 
The recent statements by Garrison (1921, p.835) in a learned work 
(1673. Leeuwenhoek makes microscopes”’), and by Mrs Williams-Ellis 
(1929, p.13) in a juvenile broadcast (1660. Leeuwenhoek has made 
hundreds of microscopes’’), are equally misleading and gratuitous guesses at 
the date. 
* Published by Derham (1726) in Hooke’s Phil. Expts. é Obss. 
® Ibid., p. 261. 
