Origin of Species, p. 293. 
320 
tertiary period at least is concerned, was of an exceptional character. 
Such a cause exists in the great and recent physical change known 
as £ The Glacial Epoch.’ ”—( The Geographical Distribution of 
Animals, vol. i., pp. 130-1.) 
And now man, for whom this world has been made a 
pleasanter place to live in by the extinction of some old 
world monsters, does his very best to complete the work 
of extinction. The slaughter of wild animals has become 
a science, and big game shooting will go on until there 
is no big game left to kill. 
We have now to consider the bearing of these facts 
upon the theory of the transmutation of species by 
Natural Selection. In the title of his great work, Mr. 
Darwin seems to imply that “ the origin of species by 
means of Natural Selection” is assured by “the preser 
vation of favoured races in the struggle for existence.” 
In the body of that work he says :—“ On the theory of 
Natural Selection, the extinction of old forms and the 
production of new and improved forms are intimately 
connected together.”* 
If Natural Selection be a real law of nature, there is 
no doubt that it will contribute to produce the survival 
of favoured races, and the extinction of those which have 
failed in the struggle for existence. But those who are 
in doubt on this subject would like to have some assur 
ance that the extinction of species can be cited as a 
proof of the transmutation of species by means of Natural 
Selection. We will consider the phenomenon from three 
points of view; (i) when the whole species is transmuted 
and ancestral forms become virtually extinct species ; 
(2) when all the members of a species are destroyed and 
their transmutation is rendered impossible ; (3) when a 
species bifurcates or ramifies, and there is possibly a