250 THE INTEGUMENT AND ORGANS OF 



5. — Speech. 



a. As the instinctive consciousness of the animal provides 

 each individual of the species with the faculty of acting in 

 co-operation with its fellows, the social, or other instrumental 

 signs or signals by which direct intercommunication is 

 effected, are comparatively simple. As human action, again, 

 is essentially dependent on man's rational consciousness, it 

 becomes an important condition of his welfare that a portion 

 of his corporeal mechanism should be such as to supply him 

 with a system of intercommunicating signals co-ordinate with 

 the universality of his conscious acts. 



b. As a special modification of the upper end of the air 

 tube is provided as the instrument of voice in man and the 

 mammalia, so in like manner the mechanism of speech is 

 provided for man alone in peculiar modifications of his buccal 

 pharyngeal and nasal chambers. 



c. The mechanism of speech is such that certain voluntary 

 dispositions of its parts induce in the air generally, during ex- 

 piration, certain sounds termed articulate sounds, which may 

 be mute or unvocalised — i.e., unaccompanied by laryngeal 

 action as in the whisper, or intoned as in ordinary speech, 

 which is produced in co-ordination with the voice. It is 

 wrong to suppose that speech is not provided for by the struc- 

 ture of the mouth. No animal has its lips pouting outwards 

 like those of a man, not even the chimpansee, in which the 

 lips are drawn together over the convex rows of the teeth. 

 Man is peculiar in the vertical direction of his teeth, the pos- 

 terior surfaces of the front teeth being adapted to the tip of 

 his tongue. The human tongue has scarcely any body, only 

 root, tip, and margin. The short-vaulted palate of man is 

 peculiar, and adapted to the dorsum of the tongue. The human 

 pharynx and fauces are peculiar in the shortness and mobility 

 of the uvula, which is the chief framer of vocal sounds. The 



