Origin of the Fittest 
subjects the marks are gained. So is it in nature. 
Natural selection takes an organism as a whole. 
One species may have established itself because 
of its fleetness, a second because of its courage, 
a third because it has a strong constitution, a 
fourth because it is protectively coloured, a fifth 
because it has good digestive powers, and so on. 
We thus perceive the part played by natural 
selection and other forms of isolation in the 
making of species. It is obvious that these 
do not make species any more than the Civil 
Service Commissioners manufacture Indian civil 
servants, 
The real makers of species are the inherent 
properties of protoplasm and the laws of variation 
and heredity. These determine the nature of the 
organism ; natural selection and the like factors 
merely decide for each particular organism whether 
it shall survive and give rise to a species. 
The way in which natural selection does its 
work is comparatively easy to understand. But 
this is only the fringe of the territory which we 
call evolution. 
We seem to be tolerably near a solution of 
the problem of the causes of the susvzval of 
any particular mutation. This, however, is 
merely a side issue. The real problem is the 
cause of variations and mutations, or, in other 
words, how species ovzgznate. At present our 
knowledge of the causes of variation and muta- 
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