But this analysis throws no light on the nature of the correct vocal action. It is impossible for the voice to produce a sound in any way other than that just described. In speaking or in singing, in laughing or in crying, in every sound produced by the action of the vocal cords, the mechanical principle is always the same. Nor is the bearing of this law limited to the human voice. Every singing bird, every animal whose vocal mechanism consists of lungs and larynx, illustrates the same mechanical principle of vocal action. Only passing mention is required of the fallacy of the breath-band theory. The idea of any necessity of relieving the vocal cords of the expiratory pressure is purely fanciful. How any one with even a slight understanding of mechanics could imagine the checking of the breath by the inflation of the ventricles of Morgagni, is hard to conceive. _The Psychology of Tone-Production_ This subject was treated, in some detail, in Chapter V of Part II. In that chapter however we were concerned more with a destructive criticism of the idea of mechanical tone-production than with the positive features of vocal psychology. At the risk of some repetition it is therefore advisable here to sum up the laws of psychology bearing on the vocal action. Considered as a psychological process, tone-production in singing involves three distinct operations. First, the mental ear conceives a tone of definite pitch, quality, vowel sound, and power. Second, the vocal organs prepare to adjust themselves, by the appropriate muscular contractions, for the production of the tone mentally conceived. Third, the fiat of will is issued, causing the muscular contractions to be performed. These three operations are executed as one conscious, voluntary act. Let us inquire to what extent consciousness is concerned with each operation. As conscious volitional impulses, the mental conception of the tone, and the fiat of will to produce the tone, are well enough understood. These two operations call for no extended consideration. We are at present concerned only with the psychological laws bearing on the muscular adjustments of the vocal organs. Muscular contractions result from the transmission to the muscular fibers of motor nerve impulses. These nerve impulses originate in the motor nerve centers. They can never, under any circumstances, rise into consciousness. Contractions of the voluntary muscles occur either as reflex or as voluntary actions. In both cases the motor nerve impulses originate in the same nerve centers. In the case of reflex actions these lower muscular centers alone are involved; in voluntary actions the originating of the motor impulses is "controlled" by consciousness. In deciding that an action shall be performed, and in what way it is to be performed, consciousness directs that each motor center involved shall send out the appropriate discharges of nerve impulse.