8 CONTENTS. 



CHAPTER PAGE 



XIII. ON THE SEA-SHORE . . .239 



XIV. IN THE TROPICAL GARDEN . .259 



XV. MAN'S FOOTPRINTS . . . 269 



XVI. THE SENSES OF PLANTS. . .281 



XVII. THE CAUSES OF THE STRUGGLE . 294 



XVIII. NATURE'S LAWS . . . . 3 T 3 



