Louis Pasteur by Nicola Kingsley - National STEM Centre

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ChaQter 4
A theory of disease
t can take a long time, often years, to collect the
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experimental evidence needed to support a scientific
theory. Pasteur was usually working on several different
projects side by side. He worked very hard,
sometimes resenting the fact that he had to stop to sleep. "I
would consider it a bad deed", he said, "to let one day go
without working".
By now he had several assistants working with him. He did
not make life easy for them. He never told them what he
was thinking and why he wanted an experiment done. He
just gave them their tasks, and expected them to get on
with it-in silence. Pasteur needed silence to work. He
could not bear to have anyone in the laboratory who was
not involved in the work he was doing. He had a particular
way of working on a new theory. He began by spending
days in isolation, reading. Then he would pace up and
down silently for days; at these times he was so wrapped up
in his thoughts that he did not notice anyone else. If
someone needed to talk to him, it took a while to attract
his attention. Then he would start suddenly and pass his
hand several times in front of his face, as if waking himself
from a dream. "Dreamy" was a word his colleagues often
used to describe him. He allowed his imagination and
intuition to work. Some of the ideas he considered were
very strange, but once a theory had taken shape in his
mind, he would put it to the test. He would make
predictions from it and tryout experiments. If the
predictions were wrong, out went the theory.
In the years following his work on the Theory of
Spontaneous Generation he was very busy. He was a
professor, teaching science. In addition to this he was
asked to help his country by solving problems that were