Then, because the horse becomes specialized and adapted to its circumstances in a remarkable manner, leaving evidence in the rocks of long severed but successive epochs, of the very manner in which it was created as we know it; and because we have proof that this method is practically self-acting, shall we stultify reason by assuming that in its self-action there is no design? that as a great rhythmic law it had no origin? that, because to our powers of observation it is automatic, it explains its own existence? or that it strips the mind, by this very automatism, of any necessity for, or right of, having its origin explained? None of these assumptions are congruous; they surely violate the fundamental principles of thought. We may be enabled no longer to say of any structure that it is a ‘final cause;’ our insight is not deep enough for that; but an equally powerful weapon in defence of theism takes its place: I designate it ‘CONCURRENT ADAPTATION;’ that is, _fitness_, for ever, throughout all time and all space; and fitness absolutely constant amidst all changes. Adaptation is universally concurrent with existence; and whether we have to account for it by sudden and unexplained action, or by the slow operation of laws, is a matter of no essential moment: _it is there_. Nothing, for example, can be more certain, than the powerful influence exerted on the coloration and morphology of flowers, all over the earth, by the visits of insects. The insects assiduously visit flowers for food, or nectar; and by their visits the pollen of one flower is carried to the stigmatic surface of another: so effecting cross fertilization. The contrivances for making insect agency efficient, are so numerous, so palpable, and so exquisitely perfect as to entrance the observer. One flower has its nectar in a tube, to reach which the proboscis of the visiting insect must touch and split a delicate tissue and expose the moist adhesive surfaces of a couple of pollen masses, which adhere to and are carried away by the insect, in such a position that, in visiting another flower of the same species, it must deposit the pollen where alone it can do its fertilizing work. Another flower is so contrived, that to reach the nectar, the visiting insect must touch a sensitive surface causing the rupture of a tissue, which confines a pollen mass; but, on the rupture of the tissue, this flies out like an arrow at the unbidden guest; and an adhesive end sticks to the insect, which is startled away; but, visiting another flower of a like kind, deposits, in the right place, the fertilizing pollen it unconsciously carries.