CONTENTS 



SECTION VI 



PAOE 



MKNTAL FACULTIES AS ACQUIRED AND INHERITED CHARACTERS 221 



The Function of the Brain . . . . .221 



Reflex Action . . . . . .222 



Intelligence, Reason, Habit (Automatic Actions), Instinct . 223 



Particular Instances of Intelligence and Reason in Animals . 231 



Experiments and Observations on Instinct in newly-hatched 



Chickens ...... 245 



The Instinct of the Cuckoo in Laying her Eggs in other Birds' 



Nests ....... 256 



Reasoning Instincts . . . . . .266 



Further Remarks on Reasoning Instincts and Intelligent In- 

 stincts in Animals . . . . .278 



Reflex Action and Instinct . . . . . .294 



Impulse and Instinct . . . . .301 



Concluding Remarks on Instinct .... 304 



Irritability and Sensation Will .... 306 



SECTION VII 



ORGANIC GROWTH : THE MORPHOLOGICAL AND PHYSIOLOGICAL EVOLU- 

 TION OF THE LIVING WORLD AS THE RESULT OF FUNCTION 315 



The Origin of Organisation in Unicellular Animals The 



Fundamental Biological Law . . . .315 



The Evolution of Organisation in Multicellular Animals . 323 

 Origin of Muscles . . . . . .326 



Origin of Striation in Muscles . . . .328 



Evolution of the various Sense-Cells from a Common Cell 



Layer ....... 331 



The Origin of the Central Nervous System . . . 331) 



Vicarious Nerve-Centres . . . . .343 



The Cell-Nucleus as a Central Nervous Organ . . 349 



