Of each of these principles I may give a simple example.  Supposing a species of bird with a soft slender beak to be placed on an island, where the only food they could obtain was fruit enclosed in a hard or tough shell or covering.  Supposing some birds accidentally possessed of a beak that was shorter and stouter than the others’, these would be able to break open the shell and get at the fruit, while the others would starve.  Some of the descendants of the birds with the stout beaks would inherit the same peculiarity, and in the course of several generations there would thus arise a species with short and strong, perhaps curved, beaks just fitted to live on fruits of the kind described.  In a similar way the webbed feet of birds that swim were developed by their aquatic habits.  And so with the long slender toes of the waders, which are so well fitted for walking over floating aquatic plants.

Of the other principle, sexual selection, a familiar example is the bright and showy colouring of the male birds of many species:  the females of their species, as they need protection while helplessly sitting on their eggs, are dull-coloured like the bark of trees or the sand, among which their nests lie hid.

Some of the Himalayan pheasants exhibit this peculiarity to a marked degree.  Originally, it is said, the male bird, which was more brightly coloured than the rest, got mated more easily by the preference shown to him for his bright colour.

The question is, can we suppose all this to go on, by self-caused laws and concurrence of circumstances, without a pre-existing design for the forms to reach or an external guidance in the processes?

CHAPTER VI.

THE MARKS OF CREATIVE INTELLIGENCE IN THE EVOLUTION OF ORGANIC FORMS.

The heading of this chapter does not mark a new departure, for we have been tracing existing forms of matter from the first, and have already seen the necessity of believing in Creative Intelligence and Guidance.  We have seen that inorganic matter, with what we call its molecular or atomic structure, cannot be reasonably regarded as self-caused; and we have concluded with Sir J.F.W.  Herschell that the sight of such a well-arranged army, performing its evolutions in a regular and uniform manner, irresistibly suggests a great Commander and Designer.  We have further found that the advent of LIFE demands a Power ab extra.  We have called attention to the gap, between plant and animal, which is ignored or made light of, chiefly on account of the close approach of the two kingdoms.  But there is one broad distinction, namely, that of elementary reason and no reason, or of consciousness and unconsciousness, which is, in itself, a sufficient difficulty to pull us up shortly.  We have not yet fully considered this matter, because it will come more appropriately at a later stage, and in the a fortiori form.  But we have