60 HAND-BOOK OF PHYSIOLOGY. 



larynx. If the palatine arches contribute at all to the production of 

 the higher notes of the natural voice and the falsetto, it can only be by 

 their increased tension strengthening the resonance. 



The office of the ventricles of the larynx is evidently to afford a free 

 space for the vibrations of the lips of the glottis; they may be compared 

 with the cavity at the commencement of the mouth-piece of trumpets, 

 which allows the free vibration of the lips. 



SPEECH. 

 



Besides the musical tones formed in the larynx, a great number of 

 other sounds can be produced in the vocal tubes, between the glottis and 

 the external apertures of the air-passages, the combination of which sounds 

 by the agency of the cerebrum into different groups to designate objects, 

 properties, actions, etc., constitutes language. The languages do not 

 employ all the sounds which can be produced in this manner, the com- 

 bination of some with others being often difficult. Those sounds which 

 are easy of combination enter, for the most part, into the formation of 

 the greater number of languages. Each language contains a certain 

 number of such sounds, but in no one are all brought together. On the 

 contrary, different languages are characterized by the prevalence in them 

 of certain classes of these sounds, while others are less frequent or alto- 

 gether absent. 



Articulate Sounds. The sounds produced in speech, or articulate 

 sounds, are commonly divided into vowels and consonants: the distinction 

 between which is, that the sounds for the former are generated by the 

 larynx, while those for the latter are produced by interruption of the cur- 

 rent of air in some part of the air-passages above the larynx. The term 

 consonant has been given to these because several of them are not prop- 

 erly sounded, except consonantly with a vowel. Thus, if it be attempted 

 to pronounce aloud the consonants , d, and g, or their modifications, p, 

 t, k, the intonation only follows them in their combination with a vowel. 

 To recognize the essential properties of the articulate sounds, we must, 

 according to Miiller, first examine them as they are produced in whisper- 

 ing, and then investigate which of them can also be uttered in a modified 

 character conjoined with vocal tone. By this procedure we find two 

 series of sounds: in one the sounds are mute, and cannot be uttered with 

 a vocal tone; the sounds of the other series can be formed independently 

 of voice, but are also capable of being uttered in conjunction \vith it. 



All the vowels can be expressed in a whisper without vocal tone, that 

 is, mutely. These mute vowel-sounds differ, however, in some measure, 

 as to their mode of production, from the consonants. All the mute con- 

 sonants are formed in the vocal tube above the glottis, or in the cavity of 

 the mouth or nose, by the mere rushing of the air between the surfaces 



