On the "delayed reaction", see Walter S. Hunter, "The Delayed Reaction in Animals and Children", Behavior Monographs, No. 6, 1913. A brief summary of this work can also be found in Hunter's General Psychology, 1919, pp. 31-33.

On the homing of pigeons and terns, see Watson and Lashley, An Historical and Experimental Study of Homing, published by the Carnegie Institution of Washington, 1915.

Interesting examples of changed organic states affecting the behavior of unicellular animals are given by Jennings in his Behavior of the Lower Organisms, 1906, and by Margaret F. Washburn in The Animal Mind, 2nd edition, 1917, pp. 246-257.

{89}

CHAPTER V
NATIVE AND ACQUIRED TRAITS