41, 348-56;
history of the concept, 420-21;
imitation as a mechanistic form of, 344, 390-407;
investigations and problems, 420-24;
language, science, religion, public opinion, and law products of, 37;
and mobility, 341;
Ormond's analysis, 340;
as a principal fundamental to all the natural sciences, 341-42, 346-48;
in secondary contacts in the large city, 360-61;
and social forces, 451-54;
and social process, 36, 421;
visual, 356-61.
_See_ Communication, Imitation, Process, social, Suggestion, and
Sympathy.

INTEREST:
in relation to imitation, 344, 391-94.

INTERESTS:
_bibliography_, 499-500;
classification of, 456-57;
defined, 456;
and desires, 456;
instincts and sentiments, 30;
natural harmony of, 550-51;
as social forces, 454-58, 458-62.

INTIMACY:
_bibliography_, 332;
and the desire for response, 329-30;
form of primary contact, 294-85.

INVERSION, of impulses and sentiments, 283, 292, 329.

INVESTIGATION, and research, 45.

ISOLATION:
_chap. iv_, 226-79;
_bibliography_, 273-77;
in anthropogeography, 226, 269-70;
barrier to invasion in plant communities, 527-28;
in biology, 227-28, 270;
cause of cultural differences, 229;
cause of dialects, 271;
cause of mental retardation, 231, 239-52;
cause of national individuality, 233, 257-69;
cause of originality, 237-39;
cause of personal individuality, 233-39, 271-73;
cause of race prejudice, 250-52;
cause of the rural mind, 247-49;
circle of, 232;
destroyed by competition, 232;
disappearance of, 866-67;
effect upon social groups, 270-71;
feral men, 239-43;
geographical, and maritime contact, 260-64;
investigations and problems of, 269-73;
isolated groups, 270-71;
mental effects of, 245-47;
and prayer, 235-37;
and the processes of competition, selection and segregation, 232-33;
product of physical and mental differences, 228-29;
result of segregation, 254-57;
and secrecy, 230;
and segregation, 228-30;
and solidarity, 625-26;
solitude and society, 243-45;
subtler effects of, 249-52.

JEW:
product of isolation, 271;
racial temperament, 136-37;
as the sociological stranger, 318-19, 323.

KLONDIKE RUSH, 895-98.

LABOR ORGANIZATIONS:
as conflict groups, 50.

LABORING CLASS, psychology of, 40.

LAISSEZ FAIRE:
_bibliography_, 563;
and competition, 554-58;
and individual freedom, 560-61;
in secondary con