relation of, to thought, [266] ff.;
spoken, originally gesture, [269] f.;
development of, [270];
unsafe guide to psychology of sentiment, [297];
embodies a theory of the self, [313], [316], [321] ff.;
disadvantages of, for science, [36], [321] ff.;
an unreliable index of mental process, [323].
Learning, [150] f., [152], [154] f.;
implies attention, [163] ff.;