382 REVIEWS—ON THE ORIGIN OF SPECIES. 
ent upon the inherent character of the brain or its representatives, 
much as the mode and power of flight in birds and other winged 
animals, depends essentially upon the conformation of the wing. 
Hence the possession of peculiar instincts in the case of neuter 
insects incapable of continuing their race (as the neuter bees, neuter 
ants, &c.,) alluded to by Mr. Darwin as of difficult explanation, 
becomes, on the older theory, easily explained. Instinct forms, so 
to say, a portion of the organization of the animal: and thus, if a 
neuter insect were so organized as to become a fertile one, its 
instinets would necessarily become modified with the other parts of 
the organization. If instinct be really capable of improvement or 
modification, as the transmutation theory is forced to assert, but of 
which not the slightest proof is afforded, instinct and reason must in 
a manner be one. But all known facts are opposed to this, although 
the two principles are sometimes confounded by the unreflective, or 
by those who are disinclined to allow a certain share of reason to the 
lower animals. Rightly considered, these principles are not only dis- 
tinct, but are actually antagonistic elements. The higher the reason- 
ing powers, the feebler or less developed become the manifestations 
of the instinct principle. 
We now come to the fourth great obstacle to the reception of Mr. 
Darwin’s views—the fertility of varieties when crossed, and the 
sterility of the offspring of separate species in the few cases in which 
these latter can be made to unite. This subject is discussed by the 
author at some length, although necessarily under a very limited 
aspect. His data are chiefly, indeed almost entirely, derived from 
the Vegetable Kingdom, and hence, are scarcely available as fair 
test-elements for the proper elucidation of the question. The 
broad, opposing facts presented by animal hybridism are left, and 
unavoidably, almost untouched ; or are masked under other more or 
less distinct inquiries : as where the author says—“ Laying aside the 
question of fertility and sterility, in all other respects there seems to 
be a general and close similarity in the offspring of crossed species 
and of crossed varieties.” Briefly, on this subject, we require to 
know why separate species (which under Mr. Darwin’s view are 
nothing more than varieties) cannot be made to breed together, or 
do not breed together in the wild state—or why, in the few 
instances in which this is effected between closely allied forms, the 
offspring are sterile—whilst on the other hand, our known varieties 
