193

D. The Social Group
1. Definition of the Group. _Albion W. Small_ 196
2. The Unity of the Social Group. _Robert E. Park_ 198
3. Types of Social Groups. _S. Sighele_ 200
4. _Esprit de Corps_, Morale, and Collective Representations
of Social Groups. _William E. Hocking_ 205

III. Investigations and Problems
1. The Scientific Study of Societies 210
2. Surveys of Communities 211
3. The Group as a Unit of Investigation 212
4. The Study of the Family 213

_Selected Bibliography_ 217
_Topics for Written Themes_ 223
_Questions for Discussion_ 224

CHAPTER IV. ISOLATION

I. Introduction
1. Geological and Biological Conceptions of Isolation 226
2. Isolation and Segregation 228
3. Classification of the Materials 230

II. Materials

A. Isolation and Personal Individuality
1. Society and Solitude. _Francis Bacon_ 233
2. Society in Solitude. _Jean Jacques Rousseau_ 234
3. Prayer as a Form of Isolation. _George Albert Coe_. 235
4. Isolation, Originality, and Erudition. _T. Sharper Knowlson_ 237

B. Isolation and Retardation
1. Feral Men. _Maurice H. Small_ 239
2. From Solitude to Society. _Helen Keller_ 243
3. Mental Effects of Solitude. _W. H. Hudson_ 245
4. Isolation and the Rural Mind. _C. J. Galpin_ 247
5. The Subtler Effects of Isolation. _W. I. Thomas_. 249

C. Isolation and Segregation
1. Segregation as a Process. _Robert E. Park_ 252
2. Isolation as a Result of Segregation.
_L. W. Crafts and E. A. Doll_ 254

D. Isolation and National Individuality
1. Historical Races as Products of Isolation. _N. S. Shaler_ 257
2. Geographical Isolation and Maritime Contact. _George