VOICE IN MAN AND IN ANIMALS. 395 



ino- obstacles: thus are formed the sounds known as consonants. In 

 setting up these obstacles, the tongue, the teeth, the lips, the soft 

 palate, play respectively a more or less important part. We readily 

 distinguish the labials, the Unguals, the dentals, the nasals. No 

 classification, however, will stand a rigid analysis ; the simultaneous 

 play of the teeth, tongue, lips, and soft palate, and the somewhat 

 doubtful character of some sounds, render all classifications more or 

 less arbitrary. 



Among the consonants are the sounds of puffing, hissing, trilling ? 

 and these are pronounced without the aid of vowels. 1 The labials 

 are formed mainly by the movement of the lips the easiest move- 

 ment of all those concerned in the utterance of speech. Accordingly 

 as the lips are closed tightly or loosely, two distinct letters are 

 pronounced ; if the closure is imperfect, a third letter is produced. 2 

 There are two letters, m and , which it is impossible to pronounce 

 with the soft palate depressed, so as to close the nasal passages. 

 Czermak introduced water into his nostrils, and then tried to pro- 

 nounce these two consonants ; the water was forced out by the passage 

 of the air. The sound of the dentals is produced by a strong pressure 

 of the tongue usually against the teeth, which, however, are not indis- 

 pensable. The gutturals are pronounced by bringing the tongue 

 back against the palate. 



All these consonants may be classed, according to the character 

 of the sound, as either surds or explosives. When the external air re- 

 mains in communication with the air expired, notwithstanding the 

 obstacle set up for articulation, the consonant may be sustained 

 during the continuance of the expiration. 3 Where there is no com- 

 munication, the duration of the sound is restricted to the instant in 

 which the obstacle is removed, and the result is a slight explosion of 

 the air. 4 This is shown conclusively when we precede a consonant 

 with a vowel, and the same experiment serves clearly to show the dis- 

 tinction between hard and soft explosives. 5 In pronouncing the former 

 the glottic orifice is narrow, the current of air is feeble, and the sound 

 persists for a moment after the mouth has opened ; in the other case, 

 the glottis allows the passage of a stronger current of air, and the 

 sound has no perceptible duration. 



Certain consonants are in English called trills ; they are produced 

 by the interruption of the breath at regular intervals, by vibrations 

 of the soft palate and the extremity of the tongue. In the soft trill, 

 the edges of the tongue produce simple oscillations of the air, but in 

 the harsh trill, the vibrations produced at once by the palate and the 

 tip of the tongue become intense. Finally, there are certain sounds 

 of frequent occurrence in English, German, and the Slavonic lan- 

 guages ; these are produced by an expiration differing from one 



1 /, s, r. 2 b, p, v. ' 2, zh, v, s. * b, p, d, t, g (hard), k, x. 



6 b, d, gh, as contrasted with p, (, k. 6 1 and r. 



