| The diversity of animal life | [177] |
| The evolution theory | [181] |
| Natural selection: not to be used as a magic formula | [183] |
| Panmixia and disuse | [189] |
| Sexual selection or preferential mating | [197] |
| Use and disuse | [209] |
| The nature of variations | [216] |
| The inheritance of variations | [223] |
| The origin of variations | [231] |
| Summary and conclusion | [241] |
CHAPTER VII.
THE SENSES OF ANIMALS.
| The primary object of sensation | [243] |
| Organic sensations and the muscular sense | [244] |
| Touch | [245] |
| The temperature-sense | [249] |
| Taste | [250] |
| Smell | [257] |
| Hearing | [261] |
| Sense of rotation or acceleration | [269] |
| Sight | [273] |
| Restatement of theory of colour-vision | [278] |
| Variation in the limits of colour-vision | [281] |
| The four types of "visual" organs | [293] |
| Problematical senses | [294] |
| Permanent possibilities of sensation | [298] |
CHAPTER VIII.
MENTAL PROCESSES IN MAN.
| The physiological aspect | [302] |
| The psychological aspect | [304] |
| Sensations: their localization, etc. | [306] |
| Perceptual construction | [312] |
| Conceptual analysis | [321] |
| Inferences perceptual and conceptual | [328] |
| Intelligence and reason | [330] |
CHAPTER IX.
MENTAL PROCESSES IN ANIMALS: THEIR POWERS OF PERCEPTION AND INTELLIGENCE.
| The two factors in phenomena | [331] |
| The basis in organic evolution | [336] |
| Perceptual construction in mammalia | [338] |
| Can animals analyze their constructs? | [347] |
| The generic difference between the minds of man and brute | [350] |
| Perceptual construction in other vertebrates | [350] |
| "Understanding" of words | [354] |
| Perceptual construction in the invertebrates | [356] |
| "The psychic life of micro-organisms" | [360] |
| The inferences of animals | [361] |
| Intelligent not rational | [365] |
| Use of words defined | [372] |
| Language and analysis | [374] |
CHAPTER X.
THE FEELINGS OF ANIMALS: THEIR APPETENCES AND EMOTIONS.