we have here everything favourable for much
modification,--for far more modification than with the Alpine
productions left isolated, within a much more recent period, on the
several mountain ranges and on the arctic lands of Europe and N.
America. Hence it has come, that when we compare the now living
productions of the temperate regions of the New and Old Worlds, we find
very few identical species; but we find in every class many forms, which
some naturalists rank as geographical races, and others as distinct
species; and a host of closely allied or representative forms which are
ranked by all naturalists as specifically distinct[62]."

[60] _Origin of Species_, p. 332.

[61] _Origin of Species_, p. 332.

[62] _Ibid_. pp. 333-4.

In view then of all the above considerations--and especially those
quoted from Darwin--it appears to me that far from raising any
difficulty against the theory of evolution, the facts adduced by Mr.
Carruthers make in favour of it. For when once these facts are taken in
connection with the others above mentioned, they serve to complete the
correspondence between degrees of modification with degrees of time on
the one hand, and with degrees of evolution, of change of environment,
&c., on the other. Or, in the words of Le Conte, when dealing with this
very subject, "It is impossible to conceive a more beautiful
illustration of the principles we have been trying to enforce[63]."

[63] _Evolution and its Relation to Religious Thought_, p. 194.

NOTE A TO PAGE 257.

The passages in Dr. Whewell's writings, to which allusion is here made,
are somewhat too long to be quoted in the text. But as I think they
deserved to be given, I will here reprint a letter which I wrote to
_Nature_ in March, 1888.

In his essay on the _Reception of the Origin of Species_, Prof.
Huxley writes:--

"It is interesting to observe that the possibility of a fifth
alternative, in addition to the four he has stated, has not dawned
upon Dr. Whewell's mind" (_Life and Lectures of Charles Darwin_,
vol. ii, p. 195).

And again, in the article _Science_, supplied to _The Reign of
Queen Victoria_, he says:--

"Whewell had not the slightest suspicion of Darwin's main theorem,
even as a logical possibility" (p 365).

Now, although it is true that no indication of such a logical
possibility is to be met with in the _History of the Inducti