Preface, by R.S. Lull.--The origin of the earth, by J. Barrell.--The earth's changing surface and climate, by C. Schuchert.--The origin of life, by L.L. Woodruff.--The pulse of life, by R.S. Lull.--Climate and evolution of civilization, by E. Huntington.--Index.

The scope of biology. Cellular organization of life. The physical basis of life. Metabolism of organisms. Survey of unicellular animals. Survey of invertebrates. The invertebrate body. Survey of vertebrates. The vertebrate body. Nutrition. Respiration. Circulation. Excretion. Reproduction. Coordination. Origin of life. Continuity of life. Fertilization. Development. Inheritance. Organic adaptation. Descent with change. Biology and human welfare. Development of biology.