Teachers usually require their pupils to obtain command of this action as a toneless exercise before permitting them to apply it to the production of tone. Methods vary greatly as to the length of time devoted to toneless drills in breathing and breath-control. Many teachers demand that students practise these exercises daily throughout the entire course of study, and even recommend that this practice be continued throughout the singer's active life. Simple as these exercises are in theory, they demand very arduous practice. Control of the breath by "opposed action" is hard and tiring muscular work, as the reader may easily convince himself by practising the above described exercise for a few minutes. No special rules are needed for applying this mode of breathing to the production of tone. Theoretical writers generally do not claim that the control of the breath brings about the correct laryngeal action, but merely that it permits this action by noninterference. Several authorities however, notably Shakespeare, maintain that in effect this system of breath-control embodies the old precept, "Sing on the breath." (Wm. Shakespeare, _The Art of Singing_, London, 1898, p. 24.) Other theorists hold that the empirical precept, "Support the tone," refers to this manner of controlled expiration. (G. B. Lamperti, _The Technics of Bel Canto_, Trans. by Dr. Th. Baker, N. Y., 1905, p. 9.) _The "Breath-band" System_ While most authorities on the voice advocate the system of breath-control by "opposed muscular action," there are a number of masters who teach an entirely different system. This is usually known as the "Breath-band," or "Ventricular" breath-control. Charles Lunn, in _The Philosophy of the Voice_, 1878, was the first to propound the theory that the breath may be controlled by the false vocal cords. There is reason to believe that this idea was also worked out independently by Orlando Steed ("On Beauty of Touch and Tone," _Proceedings of the Musical Assn._, 1879-80, p. 47). As a number of prominent teachers base their entire methods on this theory, it is worthy of careful attention. The "breath-band" theory may be stated as follows: