Characteristics of the period. Systems of flowering plants; Linnæus and the Jussieus. Réaumur and the _History of Insects_. The budding-out of new animals (Hydra); another form of propagation without mating (aphids). The historical or comparative method; Montesquieu and Buffon. Amateur students of living animals. Intelligence and instinct in the lower animals. The food of green plants. The metamorphoses of plants. Early notions about the lower plants. PERIOD IV (1790-1858) 89 Characteristics of the period. Sprengel and the fertilisation of flowers. Cuvier and the rise of palæontology. Chamisso on the alternation of generations in Salpa. Baer and the development of animals. The cell-theory. The scientific investigation of the higher cryptogams. The enrichment of English gardens. Humboldt as a traveller and a biologist. Premonitions of a biological theory of evolution. PERIOD V (1859 and Later) 124 Darwin on the _Origin of Species_. Pasteur's experimental study of microbes. Chronological Table 141 The Sub-Divisions of Biology 146 Bibliography 147 Index 149 LIST OF ILLUSTRATIONS PAGE Karl Ernst von Baer _Frontispiece_ Figure from Fuchs' "Historia Stirpium" 8 Leonhard Fuchs 10 Comparative Figures of Skeletons of Man and Bird, from Belon's Book of Birds 14, 15 Marcello Malpighi 31 Antony van Leeuwenhoek 33 John Ray 42 Carolus Linnæus 53 Georges Louis Leclerc, Comte de Buffon 65 Georges Cuvier 99 INTRODUCTION