CONTENTS 



CHAPTER I. 



Molecules and Atoms Energy free and potential Proto- 

 plasm as a transformer of energy Food The brain as 

 a transformer of energy Instinct and reason Sydney 

 Smith Definition of Instinct The Amoeba The Vol- 

 vocinae Memory and Instinct 9-30 



CHAPTER II. 



Multicellular animals Sex Hydromedusae Hydra Appear- 

 ance of nerve cells Medusoids Their nervous system 

 " Eye-spots " Purposive movements of Hydra according 

 to stimulus Purposive movements of Medusoids de- 

 pendent on existence of nervous system Purposive 

 movements of unicellular organisms accounted for 

 Development of sensory organs Light as stimulus . 3 l -$6 



CHAPTER III. 



The nervous system of the Star-fish Purposive movements 

 dependent on presence of sensory organs Development 

 of head in animals Earth-worms Rudimentary brain 

 Hereditary instinctive movements Crayfish Increased 

 complexity of brain corresponding to higher order of 

 instinctive movements^Labyrinth experiments The 

 brain of insects Their sensory organs Highly de- 

 veloped instinctive processes in Ants, etc. Automatic 

 processes 57~93 



CHAPTER IV. 



Nerve cells and nerves Spinaf cord Motor and sensory 

 nerves Reflex action The brain The Amphioxus and 

 its nervous system Fish The Lamprey and its brain 

 The basal or instinctive ganglia The development of 

 the cerebral cortex The Mud-fish The Stickleback, 

 Salmon, Perch, instinctive processes of, shown in traits 

 of character Their existence depends on presence of 

 basal ganglia Amphibians, brain of Location of centre 

 of instinctive movement Reptiles, sense organs of 



Birds . 94-124 



vii 



