278 BIOLOGY AND ITS MAKERS 
and toads and other animals arose from the mud of ponds 
and streams through the vivifying action of the sun’s rays. 
Rats were supposed to come from the river Nile, the dew was 
supposed to give origin to insects, etc. 
The scientific writers of this period had little openness of 
mind, and they indulged in scornful and sarcastic comments 
at the expense of those who doubted the occurrence of 
spontaneous generation. In the seventeenth century Alex- 
ander Ross, commenting on Sir Thomas Brown’s doubt as 
to whether mice may be bred by putrefaction, flays his an- 
tagonist in the following words: “‘So may we doubt whether 
in cheese and timber worms are generated, or if beetles and 
wasps in cow-dung, or if butterflies, locusts, shell-fish, snails, 
eels, and such life be procreated of putrefied matter, which 
is to receive the form of that creature to which it is by 
formative power disposed. To question this is to question 
reason, sense, and experience. If h2 doubts this, let him go 
to Egvpt, and there he will find the fields swarming with 
mice begot of the mud of Nylus, to the great calamity of 
the inhabitants.” 
II. From Redi to Schwann.—The second period em- 
braces the experimental tests of Redi (1668), Spallanzani 
(1775), and Schwann (1837)—notable achievements that 
resulted in a verdict for the adherents to the doctrine of 
biogenesis. Here tle question might have rested had it 
not been opened upon theoretical ground by Pouchet in 
1859. 
The First Experiments.—The belief in spontaneous gen- 
eration, which was so firmly implanted in the minds of natu- 
ralists, was subjected to an experimental test in 1668 by the 
Italian Redi. It is a curious circumstance, but one that 
throws great light upon the condition of intellectual develop- 
ment of the period, that no one previous to Redi had at- 
tempted to test the truth or falsity of the theory of spon- 
