36 THE EVOLUTION OF LIFE 
existing organisms, or (6) whether they have come 
into being in the mother liquid as a result of life- 
giving synthetic processes. 
Seeing that observation necessarily leaves the 
problem still unsolved, we are compelled to resort 
to experiment. We have to adopt, that is, certain 
artificial and unnatural conditions, which from their 
very nature must be deemed to be far less favourable 
for the processes resulting in life-origination than 
those existing in the outside world. 
The unfavourable experimental conditions are two, 
The organic fluids with which experiment has almost 
always been made, in order to free them from pre- 
existing living things, have to be subjected to degrees 
of heat which tend to degrade or partially decom- 
pose the organic matter they contain. Then, again, 
the experimental fluids are necessarily contained 
within glass vessels; and these are more or less 
impervious to the ultra-violet, or actinic, rays of 
light, often so potent in the bringing about of 
chemical combinations. 
But, on the shores of oceans, in lakes, ponds, and 
ditches these great disadvantages would not exist, 
and there would be nothing to prevent the same 
processes of life-origination occurring in all suitable 
sites and media as are postulated to have occurred 
in the far-distant past. To think otherwise would 
be to doubt the uniformity of natural processes for 
no reason whatsoever—and that even when present 
conditions may fairly be deemed, as I have already 
indicated, much more favourable for the process than 
they were originally in the absence of dissolved 
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