CONTENTS. 



PAGE. 



Introduction: Objects of the Investigation 131 



Description of the Movements and Reactions, . . . .132 



The Movements . . . 132 



The Movements of Amoeba as described Formation and Retraction of Pseudopodia 153 

 by Rhumbler and Butschli ; Agree- Surface Currents in Formation of 

 ment with Currents in a Drop of Pseudopodia in contact with Sub- 

 Fluid Moving as a Result of a Local stratum 151 



Formation of Free Pseudopodia 153 



Decrease in Surface Tension 132 ,-, , , e r, j j- 



Withdrawal of Pseudopodia 156 



Currents in Amoeba a* studied from above; Movements at Anterior Edge 160 



Lack of Backward Currents 134 Movements of Posterior Part of Body.... 165 



Movements of Upper and Lower Surfaces General View of Movements of Amoeba in 



Studied Experimentally; Rolling Locomotion 169 



Movement 138 Some Characteristics of the Substance of 



Amoeba verrucosa and Its Relatives. 140 Amoeba i?3 



Other Species of Amoeba 146 Fluidity 173 



..... T> 11- n/r Rhumbler' s Ento-ectoplasm Process 173 



Historical on Rolling Movements in 



Elasticity of Form in Amoeba 175 



Amoeba 148 r- r . i. 



Contractility in Ectosarc of Amoeba. 177 



Reactions to Stimuli 181 



Reactions to Mechanical Stimuli 181 Some Complex Activities 193 



Positive Reaction 181 Activities connected with Food-taking 193 



Negative Reaction 182 Taking Food - 193 



Reaction to Chemical Stimuli 187 Pursuit of Food 196 



Reaction to Heat 190 Other Amoebae as Food 198 



Reactions to Other Simple Stimuli 191 Reactions to Injuries 202 



Physical Theories and Physical Imitations of Amoeboid Movements, . 204 



Surface Tension Theory 204 Experimental Imitation of Movements 



Berthold's Theory that One-sided Adher- due to Local Contractions of Ectosarc 



ence to Substratum is the Cause of and of the Roughening of Ectosarc in 



Locomotion 208 Contraction 215 



Experimental Imitation of Locomo- Direct or Indirect Action of External 



tion in Ameeba 209 Agents in Modifying Movements 219 



Formation of Free Pseudopodia 214 Direct or Indirect Action in Food-taking, 222 



General Conclusion 225 



Behavior of Ameeba from Standpoint of Comparative Study of Animal 



Behavior, ............ 226 



Habits in Amoeba 226 Relation of Different Reactions to Differ- 



Classes of Stimuli to which Amoeba Re- ent Stimuli; Adaptation in Beha- 



acts 227 vior of Amoeba 327 



Types of Reaction.. 227 Reflexes and "Automatic Actions" in 



Amoeba 228 



Variability and Modifiability of Reactions 239 



Summary, 230 



130 



