374 REVIEWS—ON THE ORIGIN OF SPECIES. 
It is just as rational to assume for example, that several pairs of a 
type or species 4, differing slightly from one another but capable of 
fertile intermixture, were created with a single pair, or a smaller num- 
ber of pairs, of another species B—as to suppose that these types with 
their varieties, and in addition, other types C, D, E, F, etc., all sprang 
from an unknown type-pair, X, endowed with an innate plasticity of 
nature sufficiently accommodating to produce such changes in its de- 
scendants, as, gradually branching off in-different directions, led even- 
tually to the generation of a whale, a cat, and a sheep—not to mention 
other and more widely separated forms. This may be a rude, and in 
the eyes of those who favor Mr. Darwin’s view, a coarse and very 
unphilosophic method of putting the argument ; but it is a perfectly 
legitimate one. Granted, we say, that our system-species, which im 
many instances are not species at all, are susceptible of a certain amount 
of variation: there your argument stops. You can go no farther 
except by the help of blind and gratuitous surmises ; of surmises clothed 
certainly in attractive colours, and in some cases possessing probably 
the germs of an unseizable truth—but gratuitous, all the same, in the 
present condition of our knowledge. 
Passing over a chapter headed “the Struggle for Existence,” in 
which in brief but graphic terms, the mutual antagonism, and the no 
less mutual dependency of living forms, throughout the wide range 
of nature, is forcibly depicted, we arrive at one of the principal 
topics discussed in Mr. Darwin’s volume. This is entitled “ Natural 
Selection,’ a term employed to express the assumed tendency of 
Nature to avail itself of any slight change advantageous to a species, 
in the gradual production of varieties, and through these, of new 
types. The author appears to claim this principle of natural 
selection as a doctrine peculiar to the present work ; but, in truth— 
as shown by his own illustration of how a fleet brood of wolves 
might be produced, in this manner, by the destruction of all but 
swift-footed prey in their locality—it is essentially identical with tbe 
views of the author of the Vestiges of Creation. The latter, indeed, 
goes farther, in recognising also the full claims of climatic and other 
external causes towards the production of these changes, whilst to 
such influences, Mr. Darwin is inclined to concede no more than a 
very secondary importance. Logically considered, however, the first 
step in this principle of “natural selection,” must be more or less 
dependent, at least in most instances, on the agency of physical 
