A. _Passive Illusions (a) as determined by the Organism._ _Results of Limits of Sensibility_:--Relation of quantity of Sensation to that of Stimulus, 50-52; coalescence of simultaneous Sensations, 52-55; after-effect of Stimulation, 55, 56; effects of prolonged Stimulation, 56-58; Specific Energy of Nerves, 58, 59; localization of Sensation, 59-62; Subjective Sensations, 62-64. _Results of Variation of Sensibility_:--Rise and fall of Sensibility, 64-67; Paraesesthesia, 67, 68; _rationale_ of organically conditioned Illusions, 68, 69. CHAPTER V. ILLUSIONS OF PERCEPTION--_continued_. A. _Passive Illusions (b) as determined by the Environment._ _Exceptional Relation of Stimulus to Organ_:--Displacement of organ, etc., 70-72. _Exceptional Arrangement of Circumstances in the Environment_:-- Misinterpretation of the direction and movement of objects, 72-75; misperception of Distance, 75, 76; Illusions of depth, relief, and solidity in Art, 77-81; Illusions connected with the perception of objects through transparent coloured media, 82-84; visual transformation of concave into convex form, 84-86; false recognition of objects, 86, 87; inattention to Sense-impression in Recognition, 87-91; suggestion taking the direction of familiar recurring experiences, 91, 92. CHAPTER VI. ILLUSIONS OF PERCEPTION--_continued_. B. _Active Illusions._ Preperception and Illusion, 93-95. _Voluntary Preperception_:--Choice of interpretation in the case of visible movement, 95, 96; and in the case of flat projections of form, 96-98; capricious interpretation of obscure impressions, 99, 100. _Involuntary Preperception_:--Effects of permanent Predisposition, 101, 102; effects of partial temporary Preadjustment, 102-105; complete Pro-adjustment or Expectation, 106-109; subordination of Sense-impression to Preperception, 109-111; transition from Illusion to Hallucination, 111, 112; rudimentary Hallucinations, 112-114; developed Hallucinations, 114-116; Hallucination in normal life, 116, 117; Hallucinations of insanity, 118-120; gradual development of Sense-illusions, and continuity of normal and abnormal life; 120-123; Sanity and Insanity distinguished, 123-126. CHAPTER VII. DREAMS. Mystery of sleep, 127, 128; theories of Dreams, 128, 129; scientific explanation of Dreams, 129, 130. _Sleep and Dreaming_:--Condition of organism during sleep, 131, 132; Are the nervous centres ever wholly inactive during sleep? 132-134; nature of cerebral activity involved in Dreams, 134-136; psychical conditions of Dreams, 136-138. _The Dream as Illusion_:--External Sense-impressions as excitants of Dream-images, 139-143; internal "subjective" stimuli in the sense-organs, 143-145; organic sensations, 145-147; how sensations are exaggerated in Dream-interpretation, 147-151.