286 BIOLOGICAL LECTURES. 



PAGE 



GENERAL CONSIDERATIONS 310 



a. Instinct Precedes Intelligence 310 



b. Theories of Instinct 311 



1. Pure Instinct the Point of Departure 311 



2. Embryology and the Lamarckian Theory 312 



3. Darwin's Refutation of Lamarck's Theory. 313 



4. Weak Points in the Habit Theory 314 



c. Two Demonstrations of the Habit Theory Claimed by Romanes 314 



1. The Instinct of Pouting 316 



2. The Instinct of Tumbling 316 



d. The Habit Theory Losing Ground 318 



e. Hyatt on Acquired Characters 320 



f. Preformation the Essence of the Doctrine 321 



THE GENETIC STANDPOINT IN THE STUDY OF INSTINCT 322 



a. Genealogical History Neglected 322 



b. The Incubation Instinct 323 



1. Meaning to be Sought in Phyletic Roots 323 



2. Means Rest and Incidental Protection to Offspring 324 



3. Essential Elements of the Instinct 324 



(1) Disposition to Remain over the Eggs 325 



(2) Disposition to Resist Enemies 325 



(3) Periodicity 327 



A FEW GENERAL STATEMENTS 328 



INSTINCT AND INTELLIGENCE 331 



a. Experiment with Pigeons 332 



b. The Step from Instinct to Intelligence 333 



1. The Passenger Pigeon 334 



2. The Ring-neck Pigeon 334 



3. The Dovecot Pigeon 335 



4. Results Considered 335 



ANIMAL behavior, long an attractive theme with students 

 of natural history, has in recent times become the centre of 

 interest to investigators in the field of pyschogenesis. The 

 study of habits, instincts, and intelligence in the lower ani- 

 mals was not for a long time considered to have any funda- 

 mental relation to the study of man's mental development. 

 Biologists were left to cultivate the field alone, and psycholo- 

 gists only recently discovered how vast and essential were the 

 interests to which their science could lay claim. 



