Now here is the Ammophila, a slayer of caterpillars by a far more cunning method. Where are the professors of the art of stinging? There are not any. When the Wasp rends her cocoon and issues from underground, her predecessors have long ceased to live; she herself will perish without seeing her successors. Once the larder is stocked and the egg laid, all connection with the offspring ends; this year’s perfect insect dies while next year’s insect, still in the larval stage, slumbers below ground in its silken cot. Absolutely nothing, therefore, is transmitted by practical illustration. The Ammophila is born a finished desnucador even as we are born feeders at our mother’s breast. The nurseling uses its suction-pump, the Ammophila her dart, without ever being taught; and both are past masters of the difficult art from the first attempt. There we have instinct, the unconscious impulse that forms an essential part of the conditions of life and is handed down by heredity in the same way as the rhythmic action of the heart and lungs. Let us try, if possible, to trace the Ammophila’s instinct to its source. We suffer to-day, more than we ever did, from a mania for explaining what might well be incapable of explanation. There are some—and their number seems to increase daily—who settle the stupendous question with magnificent audacity. Give them half-a-dozen cells, a bit of protoplasm and a diagram for demonstration; and they will account to you for everything. The organic world, the intellectual and moral world, everything derives from the original cell, evolving by means of its own energies. It’s as simple as A B C. Instinct, roused by a chance action that has proved favourable to the animal, is an acquired habit. And men argue on this basis, invoking natural selection, heredity, the struggle for life. I see plenty of big words, but I should prefer a few small facts. These little facts I have been collecting and catechizing for nearly forty years; and their replies are not exactly in favour of current theories.