There are singers whose control over the registers is so expert that, when they are called upon to follow a loud, singing, vibrant head tone with a _pp_ effect on the same note, they can accomplish this by imperceptibly changing to falsetto. They can glide from head into falsetto and back again without a break and add the charm of varied tone-color to natural beauty of voice. This is especially true of dramatic tenors. If they can vary the naturally full and sonorous quality of their head tone with an artistic falsetto, they are able to secure many beautiful effects by an interchange of registers. Whenever the high tones of a lyric tenor sound thin, it is because high head tones do not lie naturally within the singer's range and he is obliged to substitute falsetto for them. "Baritone tenors" usually cannot achieve their higher notes in head register and are obliged to adopt falsetto, but as their voices are naturally fuller than those of the lyric tenor their falsetto is more agreeable. Falsetto is a remnant of the voice before mutation, the male singer who can produce falsetto having such control over the larynx that he can contract the cup space until it reverts to its original boy size. This accounts for the peculiar quality of the male falsetto--its alloy of the feminine. Boys sing soprano or alto; and a man's voice must be naturally high and possess such a genuine tenor quality that nothing can rob it of its true timbre, to be effective in falsetto. This is why the average "baritone tenors"--singers who begin as baritones but whose voices lend themselves to being trained up--rarely are able to penetrate an ensemble with a clear, ringing high note of genuine tenor quality. A good tenor falsetto is in fact a reversion to boy-soprano with, however, the quality of adult high voice predominating to such a degree that it has the tenor timbre; and in proportion as the high notes of the male voice result from artificial training instead of from natural capacity, the boy-soprano timbre will creep in and weaken the tenor quality in falsetto. Some basses and low baritones can be trained to reach the high notes of the male vocal compass in falsetto, but as natural facility to produce these notes is lacking in such voices and their production is due wholly to artifice, the reversion to the boy quality of voice is so complete and it predominates to such a degree that these voices are known as male altos. Falsetto usually is associated with tenors, but falsetto also can be employed by women, the results, as with men, depending on whether the voice is naturally a high one or not. I repeat that with voices which naturally are high, falsetto is not a "dodge," but a legitimate artistic effect. Furthermore, singers who in addition to control of the regular registers have control of falsetto, frequently find physical relief in passing from head to falsetto and back again.