VI CONTENTS OF VOL. II. 



Analogous impressions from different senses — Consciousness is indivisible — 

 Biological ground of this in nervous centralization — Sensation is divisible : 

 consciousness not — Consciousness not hereditary — Instance : how birds acqiiire 

 a dread of man Pp. 12 — 17 



CHAPTER XXIX. 



THE PHY.SIOLOGY OF MIND. 



Differentiation into organs of vegetative and of animal life — Contractility the 

 fundamental character of the latter — Nervous system developed out of mus- 

 cular — Its primary function is to transmit stimuli to the muscles — Nervous 

 system never simple — Ganglia — Pieflex action — Nervous function differentiated 

 from muscular function — Sensation does not exist at first — It begins probably 

 with special sense — Sentient and insentient nerves histologically alike — Parallel 

 development of organs and of functions —Corpora striata : their relation to the 

 sensory ganglia — Consensual action : its similarity to merely reflex action — 

 Sensation at first is only the guide to action — Insects have only this, with some 

 possible exceptions — Sensory ganglia developed out of spinal cord, and cerebrum 

 out of sensory ganglia — The cerebrum is the organ of consciousness — Largest 

 in the highest animals — Cerebrum not in direct connexion with the organs of 

 external life — Its structure — The functions of its parts can be ascertained only by 

 analogy — Phrenological theory disproved by facts — One nervous current pro- 

 ducing another — Consciousness is thus produced — Nerves and nerve-currents 

 of consciousness — Is consciousness produced in the sensoi-y ganglia or the 

 cereljrum ? — Consciousness of thought is distinct from thought — Unconscious 

 thought — Recollection without apparent cause — Nerves of thought — The sen- 

 sory ganglia are the seat of consciousness — Consciousness of thought : how 

 produced — Scat of consciousness — Memory — Its rudimentary form is a con- 

 sciousness of sensation outlasting the sensation — Recollection due to the repro- 

 duction of a current of consciousness — Consensual action produced by remem- 

 bered consciousness — Voluntary action — The same action may be at one time 

 consensual, at another voluntaiy, according to the nature of the stimulus — 

 Thought acts on the motor ganglia through the nerves of will — Position of 

 the nerves of will — Voluntary actions may become consensual — Instance of a 

 musician — This may become hereditary in animals, as in birds, and in dogs — 

 This explanation will not apply to all consensual actions — Instance of the bee 

 — Voluntary action has been developed out of consensual, and consensual out 

 of insentient — Summary — Enumeration of mental actions — Mutual relation of 

 the nervous organs of mind — Sensation — Consensual action — Consciousness of 

 sensation — Thought — Consciousness produced by thought — "Will — Reverie — 

 Sleep — Dreaming — Somnambidism — Grounds of theory stated — Functions of 

 sensory and motor nerves and ganglia are known — Those of the cerebral nerves 

 may be inferred by analogy — Cerebral nerves of consciousness, of thought, and of 

 will — Three primary mental functions probably corresponding thereto — Nerves 

 of consciousness distinct from those of thought and will — Nerves of consciousness: 

 how identified — Thought is in itself unconscious — Nerves of thought — Nerves 



