I. Introduction
1. The Concept of Interaction 339
2. Classification of the Materials 341
II. Materials
A. Society as Interaction
1. The Mechanistic Interpretation of Society. _Ludwig Gumplowicz_ 346
2. Social Interaction as the Definition of the Group in Time
and Space. _Georg Simmel_ 348
B. The Natural Forms of Communication
1. Sociology of the Senses: Visual Interaction. _Georg Simmel_ 356
2. The Expression of the Emotions. _Charles Darwin_ 361
3. Blushing. _Charles Darwin_ 365
4. Laughing. _L. Dugas_ 370
C. Language and the Communication of Ideas
1. Intercommunication in the Lower Animals. _C. Lloyd Morgan_ 375
2. The Concept as the Medium of Human Communication.
_F. Max Müller_ 379
3. Writing as a Form of Communication. _Charles H. Judd_ 381
4. The Extension of Communication by Human Invention.
_Carl Bücher_ 385
D. Imitation
1. Definition of Imitation. _Charles H. Judd_ 390
2. Attention, Interest, and Imitation. _G. F. Stout_ 391
3. The Three Levels of Sympathy. _Th. Ribot_ 394
4. Rational Sympathy. _Adam Smith_ 397
5. Art, Imitation, and Appreciation. _Yrjö Hirn_ 401
E. Suggestion
1. A Sociological Definition of Suggestion. _W. v. Bechterew_ 408
2. The Subtler Forms of Suggestion. _Albert Moll_ 412
3. Social Suggestion and Mass or "Corporate" Action.
_W. v. Bechterew_ 415
III. Investigations and Problems
1. The Process of Interaction 420
2. Communication 421
3. Imitation 423
4. Suggestion 424
_Selected Bibliography_ 425
_Topics for Written Themes_ 431
_Questions for Discussion_ 431