44 SYSTEMS OF TREATING STAMMERING stress," of "tremor," "swell and stop," and of such practices as " swelling " and " dilating " sound, etc. Vocal exercises are often taught from charts. They may then become exceedingly complex. We repro- duce below, for illustration, four charts taken from four different sources, with the symbols in each case transformed to those of a common system. The inspiration sign is that already employed (V). A dotted line indicates whispered utterance, a solid line continuous voice. Pauses are momentary unless the length of the pause is indicated in seconds by figures in parentheses. V . CHART I1 h V „ h a, V a V a V a W. a 1 Vowels are frequently placed at the extreme left of a line to show that vocalization begins immediately upon exhalation. The refinement is here disregarded.