622 VOICE AND SPEECH. 



varied modification of the sounds produced in the larynx, 

 in imitation of the modifications which voice ordinarily 

 suffers from distance, etc. From the observations of 

 Miiller 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 Miiller, much of 

 the ventriloquist's skill in imitating the voices coming from 

 particular directions, consists in deceiving 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 particuliar point, our imagination is very 

 apt to refer to that point whatever sounds we may hear. 



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 modified ; but 

 the loss of speech is confined to those letters, in the pro- 

 nunciation of which the tongue is concerned. 



CHAPTER XIX. 



THE SENSES. 



SENSATION consists in the mind receiving, through the 

 medium of the nervous system, and, usually as the result 

 of the action of an external cause, a knowledge of certain 



