CONTENTS. 



PAGE. 



Nature and Evidences of Physiological States, . . . . . in 

 Physiological States in the Protozoa (Stentor as a Type), . . .112 



Physiological States in the Lower Metazoa (the Flatworm as a Type), . 115 



Changes in the Sense of " Tropisms " and other Reactions, . . . 117 

 Changes in the Sense of Reactions with Changes in the Intensity of the 



Stimulus, 118 



Interference of Stimuli, 119 



Spontaneous Movements, . . . . . . . . .120 



Methods of Causing Changes in Physiological States, .... 120 



Nature of Reactions to Stimuli, ........ 121 



Physiological States in the Behavior of Higher Animals as compared with 



those in Lower Organisms, ........ 124 



Summary, 126 



