CONTENTS 



OHAPTEB PAGE 



I. THE SCOPE OF BIOLOGY 1 



II. THE PHYSICAL BASIS OF LIFE 6 



A. Protoplasm 7 



B. Characteristics of Living Matter 10 



1. Chemical Composition 11 



2. Metabolism 15 



3. Growth 16 



4. Reproduction 17 



5. Adaptation 17 



6. Organization 18 



III. ORGANIZATIONAL UNITS OF PLANTS AND ANIMALS . 21 



A. The Cell 23 



1. Cytoplasm . 24 



2. Nucleus 27 



B. Origin of Cells 28 



TV. METABOLISM OF GREEN PLANTS 30 



A. Structure and Life History of Sphaerella ... 30 



B. Metabolism in Sphaerella 34 



1. Food Making 35 



2. Respiration 37 



V. METABOLISM OF ANIMALS 39 



A. Structure and Life History of Paramecium . . 39 



B. Metabolism in Paramecium 41 



1. Food Taking 42 



2. Respiration and Excretion 43 



VI. METABOLISM OF COLORLESS PLANTS 44 



A. The Bacteria 44 



B. Cycle of the Elements in Nature 46 



C. The Hay Infusion Microcosm 50 



VII. THE MULTICELLULAR ORGANISM 54 



VIII. THE PLANT BODY 61 



A. Gross Structure . 65 



1. Root 65 



2. Stem 69 



3. Leaf . 71 



