58 SYSTEMS OF TREATING STAMMERING (rarely) at the larynx, when the glottis being affected, phona- tion itself becomes impeded. "By the continuance of any of these forms of spasm, a spas- modic habit is acquired, which becoming more or less auto- matic in course of time, passes more and more from under the control of the will, and eventually produces confirmed dysialia; perhaps by the vicious automatism of some nerve-centre not yet located, which may preside over the coordination of the movements of speech alone." x "The most frequent cause of stammering is the imperfect education or training of the organs of articulation, and a deficiency in that sympathetic association which ought to sub- sist between the articulating and vocal organs."2 'Tar more serious than any of the elementary defects hitherto noticed are those affections of speech which create an impedi- ment to utterance. These are known by the names of stutter- ing, stammering, spasmodic hesitation, etc. Their common characteristic is involuntary action of the organs, which are not obedient to the will. In stuttering, the articulating organs — the lips and tongue — rebound again and again before the equent vowel can find egress." 3 "If the contraction stops at the glottis, only the vowels d,re hindered; but if it extends, as it usually does, to the lips and the tongue, the consonants also are affected." 4 "The seat of the former affection, stammering, is chiefly at the larynx, or the back part of the mouth; the latter, stutter- 1 Potter, "Speech and its Defects," pp. 76-77. 2 Bishop, " On Articulate Sounds; and on the Causes and Cure of Impediments of Speech," p. 67. 8 Alexander Melville Bell, "The Faults of Speech," 5th ed., p. 9- 4 Thorpe, "Speech-Hesitation," p. 30.