I also wish to draw the attention of any one who is kind enough to look at this preface to one or two more of my illustrations, because they are, I think, of exceptional interest, and should be looked at, at once, before a decision not to read the book is made. These are the prehistoric engraving of a horse’s head, with rope-bridle in place, on page 81; the drawings of the leaves of the American Poison-vine and of the Virginian Creeper on page 95; of the nettle-sting on page 113; of the Dragon of the Hesperides on page 122; of the big tadpoles on page 217; of the jumping bean on page 298, and its moth on page 301; of the ant milking a green-fly for its honey-dew on page 324; and lastly, the accurate drawing on page 370 of the most ancient human skull yet discovered, and the other drawings of skulls (all to the scale of one-third the actual length), and those of prehistoric weapons and carvings which follow it. These drawings have been made from original scientific memoirs, or in some cases from actual specimens, for the present volume. E. RAY LANKESTER _February 1910_ CONTENTS PAGE I. SCIENCE AND PRACTICE 1 II. UNIVERSITY TRAINING 6 III. DARWIN’S THEORY 12 IV. DARWIN’S DISCOVERIES 18 V. DARWIN’S THEORY UNSHAKEN 27 VI. METCHNIKOFF AND TOLSTOI 38 VII. THE LAND OF AZURE BLUE 46 VIII. FRESH-WATER JELLY-FISHES 58 IX. THE STORY OF THE COMMON EEL 65 X. MODERN HORSES AND THEIR ANCESTORS 77 XI. A RIVAL OF THE FABLED UPAS TREE 91 XII. POISONS AND STINGS OF PLANTS AND ANIMALS 100 XIII. THE DRAGON: A FANCY OR A FACT 114 XIV. OYSTERS 128 XV. MATERNAL CARE AND MOLLUSCS 143 XVI. THE HEART’S BEAT 147 XVII. SLEEP 155 XVIII. THE UNIVERSAL STRUCTURE OF LIVING THINGS 170 XIX. PROTOPLASM, LIFE AND DEATH 180 XX. CHEMISTRY AND PROTOPLASM 187 XXI. THE SIMPLEST LIVING THINGS 193 XXII. TADPOLES AND FROGS 209 XXIII. ABOUT THE STARS 220 XXIV. COMETS 227