Free cell formation, 64. G. Geological evidence for evolution, 139. Germ plasm, 154. H. Heart as a pump, 35. Heat, 24, 44, 45. Heredity, 148, 150, 176; --explanation of, 152. Hereditary traits, 113, 153. Historical geology, 6. History of the living machine, 133, 147. Horses' toes, loss of, 172. Huxley, 11, 75, 83, 84. I. Irritability, 54. Isolation, theory of, 170. K. Karyokinesis, 96, 101. Kidneys, 41. L. Leaf, section of, 66. Life the result of a mechanism, 115, 177. Linin, 92, 103. Linnaeus, 1. Lyell, 6. Lymph, 36, 37. M. Machine defined, 20. Machines the result of mechanical forces, 116. Male cell, 104, 107. ---- pronucleus, 109. Maturation of the egg, 104. Mechanical nature of living organisms, 12. Mechanical theory of life, 81, 144. Membrane of the nucleus, 92, 101. Mental phenomena, 47, 48. Metabolism, 54. Microsomes, 87. Migration, theory of, 170. Monera, 88. Movement, 54. Muscle, 36, 71. N. Natural selection, 167. Nerve-fibre cell, 70. Nervous energy, 42, 44. ---- system, 41. New biological problems, 15. Nucleolus, 65, 92, 94. Nucleus, 65, 84, 87, 93, 101, 103, 113, 124, 149; formation of new, 101. ---- function of, 89, 90, 95. ---- presence of, 87, 88, 89. ---- structure of, 91. O. Organic chemistry, 78. Organic compounds, artificial manufacture of, 78, 82. Origin of cell machine, 178, 179, 180. Origin of life, 81, 182. Osmosis, 29. Oxidation, 80, 176. ---- as a vital process, 39, 56. P. Philosophical biology, 4. Physical basis of life, 75. Polar cells, 107. Potato, section of cells, 67. Properties of chemical compounds, 79. Protoplasm, 14, 74, 82, 83, 84, 114, 115, 179. ---- artificial manufacture of, 82. ---- as a machine, 86, 178. ---- discovery of, 74. ---- nature of, 76. ---- structure of, 86, 87. Purpose _vs._ cause, 11, 12. R. Reaction against the cell doctrine, 117. Reign of law, 4. ---- of the nucleus, 91. ---- of protoplasm, 81, 85. Relationship, significance of, 143. Removal of waste, 39, 40. Reproduction, 54, 80, 124, 148, 176; --rapidity of, 149. Respiration, 37. Reticulum of cell, 87; --of nucleus, 92. Root tip, section of, 66. S. Schultze, 74, 75. Schwann, 61, 62, 72. Secretion, 39, 40. Segmentation nucleus, 110. Sensations, 46. Separation of chromosomes, 100. Sexual reproduction, 102. Spermatozoan, 107, 109, 154. Splitting of chromosomes, 99. Spindle fibres, 101. Struggle for existence, 168. Summary of Part I, 128. ---- general, 182. U. Undifferentiated protoplasm, 83. Unicellular animals, 71. Units of vital activity, 53. Use and disuse, 171, 172. V. Variation, 148, 157, 160, 176. Variation from sexual union, 162. Variation in germ plasm, 161. Vegetative functions, 41. Villi, 31. Vital force, vitality, 13, 15, 34, 37, 52, 80, 85. Vital properties, 54; --located in cells, 123. W. Wing compared with arm, 144. Wood cells, 68. THE END. ==THE LIBRARY OF USEFUL STORIES.==