I

Idiocy, [24], [51], [254];

increase of, [289].

Ill-health in woman, [240].

Imbeciles, [25].

Incident, as social force, [287].

Industry: and sex, [123]-46;

organization of, by man, [230].

Infant mortality, [43].

Infibulation, [177].

Ingenuity in lower races, [277].

Inhibition: and art, [283];

in lower races, [263].

Initiation, [90], [153].

Insanity, [24], [51], [254];

increase of, [289].

Insomnia, [35].

Instincts, persistence of, [99].

Intelligence and culture, [260].

Interest, hunting-pattern of, [280].

Interests of savage and civilized, [279].

Invention: and labor, [230];

based on analogy, [278];

psychology of, [277].

Inventiveness of man, [146].

Irving, [140].