The method by which habits are ordinarily educed consists essentially in presenting a problem whose solution depends on the slow, and often painful suppression of irrelevant actions, and the survival of only those that count. The results so achieved are invaluable, but from the nature of the case difficult to verify. So much time is required that students of all classes are apt to be told in words, rather than by actual experiments, what has been accomplished in this interesting field. Habits formed slowly and gradually are not only incapable of quick demonstration, but the "slow method" leaves altogether untouched, a wide range of behavior. Animals do not always act slowly; they do not always overcome, with deliberation and care, the difficulties that block

1 Directly, as well as indirectly, I am indebted to Miss Frances J. Dunbar, and to Miss Nina Gage, for many of the results on which the present communication is based.

THE JOURNAL OF COMPARATIVE NEUROLOGY AND PSYCHOLOGY, VOL. 20, NO. 3.