34 SYSTEMS OF TREATING STAMMERING and exhaling in short breaths, and occluding the glottis at the end of each inhalation and exhalation. In these exercises the "click of the glottis" can be heard as the vocal cords separate after complete con- tact. It is to this particular feature, and to the feeling of glottal action, that the pupil is admonished to attend. An exercise that is sometimes prescribed for strength- ening the laryngeal muscles and making them "more pliable and subservient to the will" is practising the different vowels in octaves. The stammerer begins by singing the vowels in the lowest possible pitch. He produces them a number of times in this manner, and then practises them in a pitch an octave higher. Later the pitch is raised again, and finally the stam- merer sings the vowels in the highest pitch that he can comfortably produce. As the work progresses, the exercises become more complex, and the pupil is re- quired to jump rapidly from one pitch to another, to change the vowels as he alters the pitch, and so on. The instructor usually indicates the pitch required by striking the appropriate notes on a piano. "The pupil should, in addition, make the following exercise: utter the whole sentence in the manner of the chromatic scale; that is, begin with a high tone and descend a half tone with each syllable; and having reached the end of the sentence, repeat it in like manner but with each syllable ascending a halftone."