62 HAND-BOOK OF PHYSIOLOGY. 



All sounds of the first or explosive kind are insusceptible of combina- 

 tion with vocal tone ("intonation"), and are absolutely mute; nearly all 

 the consonants of the second or continuous kind may be attended with 

 ' 'intonation." 



Ventriloquism; The peculiarity of speaking, to which the term 

 ventriloquism is applied, appears to consist merely in the varied modifi- 

 cation of the sounds produced in the larynx, in imitation of the modifica- 

 tions which voice ordinarily suffers from distance, etc. From the obser- 

 vations of Muller and Colombat, it seems that the essential mechanical 

 parts of the process of ventriloquism consist in taking a full inspiration, 

 then keeping the muscles of the chest and neck fixed, and speaking with 

 the mouth almost closed, and the lips and lower jaw as motionless as 

 possible, while air is very slowly expired through a very narrow glottis; 

 care being taken also, that none of the expired air passes through the 

 nose. But, as observed by Muller, much of the ventriloquist's skill in 

 imitating the voices coming from particular directions, consists in deceiv- 

 ing other senses than hearing. We never distinguish very readily the 

 direction in which sounds reach our ear; and, when our attention is 

 directed to a particular point, our imagination is very apt to refer to that 

 point whatever sounds we may hear. 



Action of the Tongue in Speech. The tongue, which is usually 

 credited with the power of speech language and speech being often 

 employed as synonymous terms plays only a subordinate, although very 

 important part. This is well shown by cases in which nearly the whole 

 organ has been removed on account of disease. Patients who recover 

 from this operation talk imperfectly, and their voice is considerably mod- 

 ified; but the loss of speech is confined to those letters in the pronuncia- 

 tion of which the tongue is concerned. 



Stammering depends on a want of harmony between the action of 

 the muscles (chiefly abdominal) which expel air through the larynx, and 

 that of the muscles which guard the orifice (rima glottidis) by which it 

 escapes, and of those (of tongue, palate, etc.) which modulate the sound 

 to the form of speech. 



Over either of the groups of muscles, by itself, a stammerer may have 

 as much power as other people. But he cannot harmoniously arrange 

 their conjoint actions. 



