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LEROY F. THOMPSON. 
organisms. So, therefore, with these conditions present the 
spontaneous generation of these bacteria was opposed by some 
and supported vigorously by others of the best scientists of the 
time. So following this controversy experiments were carefully 
planned and a great variety of materials used, paving the way 
for the development later of the laboratory technique of the 
bacteriologist. 
The value of various agents were therefore demonstrated in 
a short time, such as the antiseptic action of certain chemicals, 
sterilizing action of heat and the value of the cotton plug as a 
bacterial filter, were demonstrated. The theory of spontaneous 
generation was eventually overthrown and ceased to be a topic 
of contention about i860. This was largely brought about by 
the efforts of Pasteur who, by a long series of ingenious experi¬ 
ments, overthrew the last defense of the supporters of the Abio- 
genisis theory. The dictum, “ all life from life,” is universally 
accepted at this time and the controversy has little but historic 
interest. 
The causal relationship of micro-organisms to decay and par¬ 
ticularly to fermentation was first definitely established by the 
work of this same ingenious laboratory man, Louis Pasteur, 
who lived between the years 1822 and 1895. 
He found that the production of alcohol and carbon dioxide 
from sugar was due to yeast, that milk soured because of the 
activity of bacteria, and that many of the familiar changes in 
organic substances were accomplished by micro-organisms. His 
conclusions were strenuously opposed as well as ridiculed by the 
great German chemist, Liebig. 
Doubtless the necessity for meeting the attacks of the latter 
and of establishing his points beyond possibility of refutation 
led him to devise and develop many of the laboratory methods 
in common use at the present time. 
As a result of the Pasteur work the fundamental importance 
of bacteria in the transformation of nitrogen and carbon com¬ 
pounds in nature, the disposal of waste, the purification of water, 
