Chapter XXI

PEREZ, M., 408

Personal Identity, 201; mutations of, 205 ff.; alternating personality, 205 ff.

Personality, alterations of, 205 ff.

Philosophy, Psychology and, Epilogue, 461

Phosphorus and thought, 132

Pia mater, 82

Pigeons' lower centres, 96

Pitch, 54

Pituitary body, 82, 89

Place, a series of positions, 341

Plasticity, as basis of habit, defined, 135

PLATO, 240

Play, 407

Pleasure, and pain, as springs of action, 444

Psychology and Philosophy, Epilogue, 461

Pons Varolii, 79, 84, 108

Positions, place a series of, 341

Practice, improves discrimination, 252

Present, the present moment, 280

Pressure sense, 60

PREYER, 406

Probability determines what object shall be perceived, 316, 329

Problematic conceptions, 240

Problems, solution of, 272

Projection of sensations, eccentric, 15

Psychology, defined, 1; a natural science, 2; what data it assumes, 2; Psychology and Philosophy,