14 SYSTEMS OF TREATING STAMMERING either measured by a metronome, or is given by an instructor, who leads the class with a baton or beats time with the hand. In some institutions charts are dispensed with, and the instructor leads the class with a baton and gives directions orally or by gestures. When the pupils practise alone, they usually take the time from a metronome or count mentally. In many institutions the various sets of breathing- muscles — the chest muscles, intercostal muscles, dorsal muscles, etc. — are exercised separately. The following exercises are quite commonly prescribed: Upper Chest Breathing! — Place the hands upon the chest, with the tips of the fingers on the clavicles. Inhale slowly, filling the upper part of the thorax so that the expansion can be distinctly felt beneath the hands. Inhibit movements of the shoulders, and as far as possible movements of the muscles controlling the lower part of the thorax. Exhale slowly when the upper chest has been fully expanded. Practise the various simple respiratory exercises, using upper chest breathing. Costal Breathing? — Place the hands upon the lower ribs, with the fingers pointing forward and the thumbs back. In- hale slowly, expanding the lower thorax laterally so that the movement can be felt beneath the hands. Suppress upper chest breathing as far as possible. Exhale slowly after inhala- tion is complete. Practise the simple exercises, employing costal breathing. Exercise the costal muscles unilaterally, effecting the move- ment first on the left side and then on the right. 1 Also designated clavicular breathing, collar-bone breathing, shoulder breathing, etc. 2 Also designated lateral breathing, side breathing, rib breathing, etc.