What if to-morrow an engineer should plant a cannon ball.

Having watered it well and kept the ground loose through hoe or spade, suppose that when a few weeks have passed the outline of a smokestack should push through the soil, to be followed a little later by a rudimentary steam whistle, the outlines of a boiler, and, rising through the sod, rude drive-wheels, piston-rods and cylinders, until after six months the great engine should stand forth in full completion.

This phenomenon would be no more wonderful than that which actually goes on before man's blind eyes, when a tiny seed enlarges into the big tree of California and constructs a vegetable engine that lifts thousands of hogsheads of water up to the topmost boughs without any rattle of chains or the din of machinery.
With difficulty man constructs that musical instrument called a mouthharp, but nature, in six weeks, out of a little blue or brown egg constructs a feathered music-box that automatically conveys itself from tree to tree.

But the mystery that has gone on in that tiny blue egg lying in the nest is just as great as if some housewife had planted an old spinning-wheel in the full expectation of reaping a Jacquard loom, or had buried a jew's-harp in the garden expecting in the fall to pick a grand piano.

To the mystery that is involved in enlargement by growth must be added the mystery of intelligence.