INTRODUCTION OF THE MICROSCOPE 77 
In reference to the formation of animals within the egg, 
Swammerdam was, as Malpighi, a believer in the pre-forma- 
tion theory. The basis for his position on this question will 
be set forth in the chapter on the Rise of Embryology. 
There was another question in his time upon which philos- 
ophers and scientific men were divided, which was in reference 
to the origin of living organisms: Does lifeless matter, some- 
times, when submitted to heat and moisture, spring into life? 
Did the rats of Egypt come, as the ancients believed, from 
the mud of the Nile, and do frogs and toads have a similar 
origin? Do insects spring from the dew on plants? etc., etc. 
The famous Redi performed his noteworthy experiments 
when Swammerdam was twenty-eight years old, but opinion 
was divided upon the question as to the possible spontaneous 
origin of life, especially armong the smaller animals. Upon 
this question Swammerdam took a positive stand; he ranged 
himself on the side of the more scientific naturalists against 
the spontaneous formation of life. 
ANTONY VAN LEEUWENHOEK (1632-1723) 
In Leeuwenhoek we find a composed and better-balanced 
man. Blessed with a vigorous constitution, he lived ninety- 
one years, and worked to the end of his life. He was born 
in 1632, four years after Malpighi, and five before Swammer- 
dam; they were, then, strictly speaking, contemporaries. 
He stands in contrast with the other men in being self-taught; 
he did not have the advantage of a university training, and 
apparently never had a master in scientific study. This lack 
of systematic training shows in the desultory character of his 
extensive observations. Impelled by the same gift of genius 
that drove his confréres to study nature with such unexampled 
activity, he too followed the path of an independent and 
enthusiastic investigator. 
