Instinct, 238, 240, 247, 249, 250, 251, 252, 254, 256, 257, 259, 263, 264, 265, 267, 291, 343, 361; defined, 255, 256; James’ definition of, 249; according to external circumstances, 250-252; according to physiological state of organism, 250; adjustment of, 250, 252; constructive, 251; effective only under normal circumstances 258; evolutionary origin of, 267 —improbable, 267; fixity of, 258; improbability of, 267; its regulatory principal sense, 254; not gradually acquired, 263, 264; not intelligence, 254; only slightly undefiable, 256; origin of, 263; psychic regulation of, 249; requires no apprenticeship, 256; teleology of, 249; telic, 259; variability of, 250 Instinctive acts, 256 Instruction, 244, 245 Instrumentation, 197 Intellect, 220, 221, 224, 226-230, 339; active, 220, 221; activity of, 221; cognitive, 220, 221; conscious of its own operations, 226, 227; indirectly dependent on physiological condition of cortex, 221; its immaterial nature, 224; objectively dependent on organic activity of imagination, 221; not bound to material organ, 226; not debilitated by intense thinking, 227, 228; not incapacitated but invigorated by intense thinking, 228; not regulated by physiological vicissitude, 229; not subject to metabolic laws, 230; rooted in a spiritual principle, 227; superorganic nature of, 227 Intellectual, 228, 229, 230; activity may reach highest points of concentration and intensity without involving commensurate fatigue on part of organism, 228 Intelligence, 239-241, 243, 245, 247, 248, 249, 254, 256, 257, 259, 262, 263, 267, 329, 330, 340, 343, 350; definition of, 239; autonomous, 259; a generalizing and abstracting power, 257; “bestial,” 245, 247, 257; conscious, 240; deceptive semblance of, 240, 241; Divine, 249; etymology of, 239; finite, 249; genuine, 240, 241; infinite, 248, 249; incapable of being evolved from matter, 267; inherent, 249, 256, 259, 267; of worker bees, 267; subjective or inherent, 248, 249; used to denote power of profiting by experience, 239, 240 Intensity, 227, 230; does not increase in same proportion as intensity of stimulus, 227; may reach maximum with involving corresponding fatigue, 230; of thought does not follow fluctuations of neural metabolism, 230 Interactionism, 206 Interaction, three types of, 175 Interglacial period, 329; last, 329 Intergradation, 87 Intergradence, 84-87; may indicate hybridism, 84, 85; no argument for common ancestry, 84-86; of mutants genetically independent, 85, 86