Wise men can, indeed, imitate this device, but a single seed will in a few months construct many scores of these mechanical devices.

To-morrow morning the embryologist in his laboratory will place an egg under a glass cylinder in an atmosphere of 98 degrees.

Four hours pass and suddenly the scientist perceives an atom in the heart of that egg give a quick lashing movement.

Another moment witnesses two quick throbs.

Growth has begun and in four months' time the young eagle with firm strokes will lift itself into the soft air.