XVI
CONTENTS.
merits, b. Association of movements and ideas.—1. Voluntary association of move¬
ments with each other. 2. Association of movements with ideas, c. Instinctive
movements. Nature of instinct, d. Co-ordinate movements.—Influence of the cere¬
bellum and spinal cord on the co-ordination of movements, . . . 674-677
Chap. III.—Of the movements of locomotion.—Animals destitute of locomotion.
Different kinds of locomotion in other animals. Bones,—their composition and
structure. Organs of support. Motion. Mechanism of locomotion. Swimming.
Walking and running. Mechanism of the articulations—researches of E. Weber.
Mechanism of walking and running. Leaping,...... 677-687
SECTION III.—Of voice and speech.
Chap. I.—I. Of the general conditions for the production of sounds.—Cause of sound.
—Sonorous vibrations. The siren. II. Of the voice; of the organ of voice and
other means for the production of sound in man and animals. 1. Of the human
voice. A. Of the larynx.—Of the forms which the glottis can assume. Form of
the glottis daring the emission of voice. B. Of the modulation of the voice, and
the causes on which it depends.—Experiments on the human larynx removed from
the body. State of the glottis necessary for the production of sound. Effect of
varying tension of the vocal cords. Artificial production of the natural and falsetto
notes. Effect of increasing the force of the blast of air. Action of the thyro¬
arytenoid muscles, &c. Different length of the vocal cords in the male and the
female larynx. Influence of the trachea and vocal tube in front of the glottis on
the voice. The epiglottis. The fauces and uvula. The ventricles of the larynx.
C. Theories of the voice. 1. The human organ of voice a reed instrument.—Theo¬
ries of Savort. Ferrein. Dodart and Liscovius. D. Of singing.—1. Compass of
voice. 2. Varieties of voice in different individuals. 3. In one and the same per¬
son.—Natural and falsetto. 4. Differences of the voice as to tone. 5. Strength of
the voice. 6. Increase and diminution of the intensity of the vocal sounds. 7.
Perfectness of the tones. Remarks on the artificial construction of a vocal organ.
2.0/ musical sounds formed in the mouth.—Whistling. 3. Of the voice of mamma¬
lia and reptiles. 4. Of the voice of birds.—Structure of the organ of voice in birds.
Theory of the voice in birds. 5. Sounds produced by fishes, . . . 687-700
Chap. II.—Of Speech.—Classifications of articulate sounds. A. Mute sounds of the
whisper.—I. Mute vowels. II. Mute continuous consonants. III. Mute explosive
consonants. B. Sounds of vocalised speech.—I. Vowels. II, Consonants which
remain mute in vocalised speech. IIÏ. Consonants which in vocalised language
can be pronounced either as mule sounds or with vocal intonation. Speaking ma¬
chines. Birds uttering articulate sounds. C. Ventriloquism. D. Defective speech,
—stammering, ......... . 700-706
BOOK VI.
OF THE SENSES.
Preliminary Considerations.—All sensations may be excited by internal causes in¬
dependent of external stimuli. One and the same cause, internal or external, may
excite different sensations by acting on different senses. The sensations peculiar
to each sense may be excited by several different causes, internal and external.
Nature of sensation. The nerves of each sense are capable of one determinate kind
of sensation only. Is the cause of the difference of sensations seated in the nerves,
or in the parts of the brain with which they are connected? Relation of the senses
to different external objects, agents and actions. Influence of the mind on sensa¬
tions,—first sensations of the child,—distinction between the percipient self and the
external world,—reference of the sensations to the exterior objects. Influence of
the “ attention” on the intensity of sensations. Limited number of the senses.
What would constitute a new sense? ..... 707-719
SECTION I.—Of Vision.
Chap. I.—Possible forms of organs of vision.—II. Eyes of man and vertebrate ani¬
mals. Appendages of the eyes.—The eyelids. Tunics of the eye. Transparent
media of the eye. Optic nerve and retina. Structural conditions necessary for
vision. Pretended vision independent of the eyes in the Mesmeric states. III. Pro¬
cess of vision in eyes with concentrating dioptric media. Formation of the image
by the refracting media. Angle of vision—angulus opticus. Direction and point
of decussation of the visual rays. Conditions essential for distinctness of vision.
Action of the iris. Unequal density of the lens. Use of the pigmenlum nigrum