3GO PULMONARY MUCOUS TISSUE. 



been enabled to discover the mechanism by which the vowels 

 are produced. The vowels are essentially notes produced 

 by the passnge of the air through the pharyngeal and buccal 

 cavities ; these are arranged in a special manner, and, con- 

 sequently, resound differently as each vowel is pronounced. 

 When a vowel is pronounced in a whisper, the glottis takes 

 no part in the process, the sound being produced simply by 

 the passage of the air through the supra-glottidal cavities, 

 which at that moment are so arranged as to give utterance 

 to the vowel in question ; when the same vowel is pronounced 

 aloud, the supra-glottidal cavities, arranged as before, produce 

 the effect of reinforcing those harmonics existing in the 

 sound made in the glottis, which exactly correspond with 

 those of the vowel to be pronounced. In other words, the 

 buccal and pharyngeal cavities act as sounding boards, which 

 may be variously harmonized. 



We cannot carry this analysis any farther here; it belongs 

 to the domain of pure physics, and we will only add that the 

 form assumed by these cavities for the utterance of the differ- 

 ent vowels, has been clearly ascertained, and that when the 

 cavities are properly arranged, if the wind from a pair of 

 bellows be made to pass before the mouth, even though the 

 breath be held back, sounds are heard exactly resembling 

 vowels pronounced in a whisper. In general it may be said 

 that "the longitudinal diameter of the pharyngo-buccal 

 cavity is reduced, and its transverse diameter increased by 

 the vowel-sounds ah, a, and e (a, e, i) ; while in pronouncing 

 the vowel-sounds o and u, the longitudinal diameter is in- 

 creased and the transverse diameter diminished. The move- 

 ments of the different parts of the cavity follow this general 

 disposition. The lips make a horizontal movement, which is 

 more and more decidedly antero-posterior in the case of the 

 three first vowels, and anterior in that of the two latter. In 

 pronouncing o and u, the tongue is drawn backward, while 

 in a and e, it is more or less thrown forward. The move- 

 ments of the cheeks, the velum of the palate, the uvula, and 

 the pillars of the fauces, all unite in carrying out this general 

 arrangement, etc. etc." (Mandl, op. cit.). 



The consonants, which form the second element of articu- 

 late speech, are not sounds, like the vowels, but rather irreg- 

 ular vibrations, too confusedly mingled to be separately 

 distinguished (see Hearing} ; they are sounds which cannot 

 be distinctly heard by themselves, but differ by the manner 

 in which they begin or finish the utterance of a vowel. The 



