ON CLASSIFICATION. 
17 
On the other hand, if the two fishes really belong 
to different species, we will generally be able to find 
several points of difference ; in fact the more carefully 
we study them the greater number of distinctions 
will be found. 
Between two varieties there is an apparent difference, 
but no real distinction. 
Between two species there may be a strong 
apparent similarity, but there is a real divergence 
in numerous respects of which we can usually dis- 
cover more than one, at any rate, by careful scru- 
tiny. 
It must not be imagined that, because some species 
are variable, therefore a species as such has no de- 
finite existence. True, the species of to-day may 
be different from what they will be a thousand 
or a million years hence ; some may have become ex- 
tinct, others may have given birth to many new 
species, all varying from the original, but at any one 
time such species as exist are actual and clearly 
defined entities. In this they may be compared to 
the words in a language, derived from remote roots, 
constantly varying in the course of ages, yet each 
separate and distinct at any given time from all other 
words. In the same way as with species, words may 
appear similar and yet be widely different, or they 
may seem very distinct in outward appearance and 
yet be radically the same in point of fact. 
This argument, it may be observed, does not imply 
the acceptance of the Doctrine of Evolution. It 
c 
