130 Notices of Books . [January, 
between the plant and the animal, — a task already accomplished, 
— and even attacking that “ which has been ereCted between the 
domains of organic and inorganic nature it is strange, we say, 
to find such an author suddenly arrested by the dim and eva- 
nescent boundary line which alone lies between those respective 
groups which we call species, and which he considers as primor- 
dially distinCt. He declares, indeed, that “ the doCtrine of unity 
in diversity, and diversity in unity, has little or no bearing, direCt 
or indirect, upon the doCtrine of Evolution.” If so, why does 
he append his attack upon Evolution to a work devoted to 
pointing out “ traces of unity ?” His only argument against 
Organic Evolution, beyond his declared ignorance of “ any evi- 
dence which ought to lead to a different conclusion ” seems to 
lie in the following passage : — “ And what other conclusion can 
be drawn from the infertility of mules than this — that there is a 
barrier between different species, even between those which are 
most closely akin to each other, by which they are kept apart 
most effectually.” That such lines can still be written by a man 
of learning is to us a mystery. Shall we never be delivered from 
the errors deduced from that unfortunate faCt that the best-known 
hybrid, the mule, happens to be barren ? The fertility of the 
leporide — the hybrid between the hare and the rabbit — has been 
recently most fully confirmed in a paper in “ Les Mondes,” an 
organ bitterly hostile to Evolutionism. In a recent and valuable 
monograph on the American bison we have satisfactory evidence 
that this animal can produce permanently fertile hybrids v/ith 
the domestic cow ; yet the two belong not merely to distinCt 
species, but to distinCt genera ! But to any candid enquirer we 
think the recent researches of Mr. Darwin on the reproduction 
of plants must supply full proof that the difficulty of producing 
hybrids, and their infertility where it exists, is due to causes very 
different from a supposed barrier between species, and supplies 
no valid argument against Evolution. Dr. Radcliffe concludes 
that “ each creature was created as a necessary part of a great 
whole, perfect in itself, and perfeCt in its relations to other crea- 
tures and to the universe to which it belongs ! ” But he gives 
us no proof of this alleged perfection, no standard by which it 
can be judged or recognised. If each animal was necessary, 
why do we see so many blanks in the animal series which have 
not been filled up ? Why do strange plants and animals, artifi- 
cially introduced into any country, often displace its original 
flora and fauna ? In faCt, there is scarcely a phenomenon con- 
nected with animal geography, or with the powers and functions 
of animals, which can be fairly reconciled with the creed of the 
old Natural History as here summarised by our author. 
We have no sympathy with materialists, but we cannot forget 
that every important step in the development of science has 
been met with charges of materialism and atheism. From all we 
can gather from this work, its author, both by disposition and 
