vi PREFACE. 
tioned. This time-serving and popular verdict 
once announced, was received with all the more 
readiness, because others, not having exercised the 
necessary care, had for a time failed to confirm 
my results. Now, however, that the facts have 
been substantiated and are generally acknow- 
ledged, the subsequent course of events has made 
it useful to ask, Why the majority of persons com- 
petent to judge, previously received the statements 
referred to with so much incredulity ? 
To this question only one answer can be given. 
The results were discredited because it was a 
generally accepted belief amongst men of science 
that exposure to the temperature of boiling water 
would have killed all pre-existing Living Matter 
within the flasks. And this being the case, the 
appearance of swarms of Bacteria in the experi- 
mental fluids in the course of a few days could 
only be explained by the supposition that what 
has been called ‘Spontaneous Generation’ had 
occured. To acknowledge this, however, was rank 
heresy, and was in opposition to some of the: most 
cherished and sacred beliefs of many men of science. 
In such an emergency what were scientific in- 
