Xll CONTENTS 



PAGE 



Receptors 1 58 



Vibrations I59 



The Neuron, a Structural Unit 163 



Pathways in the Old Brain Are Older Than Man . 164 



Synapse 168 



CHAPTER X 



Biological Discussion of the Problem of Learning 



Man Gains His Information Through Receptors . . 174 



The Neuron and Receptors I77 



The Problem of Learning in the Earthworm . . . 180 



The Problem of Learning in the Frog 183 



The Problem of Learning in the Racoon . . . . 185 



Trial and Error 192 



Man Is Subject to the Same Laws as Animals . . . I95 



CHAPTER XI 



Biology and Progress 



Scientific Method I99 



Its Origin 199 



Darwin's Method 200 



The Scientific Method Analysed 201 



Value of the Scientific Method 204 



Some Unsolved Problems 206 



