66 EVOLUTION AND THE 
the right to call it ‘living’ matter. As scientific 
men, we distinguish one body or class of bodies from 
another by the fact of their possessing certain dis- 
tinctive attributes or properties—and happily, in this 
respect, common usage does not differ from scientific 
usage. No one would think of calling any metal 
‘gold’ unless it possessed the combination of pro- 
perties peculiar to: gold; no physicist would call a 
“body a ‘magnet’ unless he could show that it. 
possessed magnetic properties; no chemist would 
call a fluid ‘alcohol’ unless he could show that such 
fluid possessed the known properties of alcohol, and 
similarly no biologist would call a body ‘living’ 
unless it possessed those attributes or properties 
which we are accustomed to regard as fundamental 
or characteristic. Again, no man of science would 
dream of crediting living matter in an imaginary 
case with properties different from those which he 
has on all previous occasions found it display—if he 
had reason to believe that it existed in any given 
medium, he would of course look for it on the basis 
of its known properties, just as a chemist would 
search for gold in any solution thought to contain 
it, by having regard only to its accustomed or known 
properties. The man of science necessarily starts 
from and assumes the truth of the ‘uniformity’ of 
natural phenomena at every step—to do otherwise, 
