322 
likeness does not admit of considerable difference, and 
vice versâ ; and any definition of the fixity of species 
which makes species to depend upon continuous fertility 
of the offspring, and not on likeness, is really only a 
statement of the transmutation of species, in other and 
somewhat perplexing terms. 
It seems to me to be a far more reasonable definition 
of species to declare that it is a distinction introduced 
by man in his attempt to classify the different kinds of 
living creatures which may be, and often has been, a 
merely provisional classification. In this case there can 
be no doubt that the transmutation of a whole species 
involves the extinction of ancestral forms and the sub 
stitution of what is, in effect, a new species. In this 
sense, the poet salutes aspiring man as “ the herald of a 
higher race,” and bids him to— 
. . “ move upward, working out the beast, 
And let the ape and tiger die.” 
Moreover, this fact in itself only testifies to a quasi ex 
tinction of species as the precursor and accompaniment 
of transmutation of species. It does not necessarily sug 
gest any proof as to the manner in which transmutation 
has been brought about. It would be a mere begging 
of the question to assert that, because transmutation has 
been accompanied by extinction, such extinction may be 
cited as a proof of the action of Natural Selection. 
In the second place, the extinction of a whole species 
in the ordinary sense of that word, by whatever cause 
it may be brought about, prevents the transmutation of 
that species. 
“ He that fights and runs away 
May turn and fight another day ; 
But he that is in battle slain 
Will never rise to fight again.”—(Ray.)