Avoid local muscular effort whenever you can do so, but use common sense all the time in everything. Do not tell pupils to relax, because they cannot do so, and even if they do so seemingly, they will not get correct [larynx] action, which is not relaxation. Do not tell singers to “think” tones somewhere. Avoid all confusing language, and do not play with psychology unless you are very much of a psychologist. Do not tell pupils to open their throats, because they cannot do so without causing all kinds of tensions which will only ruin correct coordinate action. And remember that expression has a vital effect upon technique, and that you should stimulate correct concept and imagination, and therefore imitation from the very beginning; imitation of his own best efforts on the part of the pupil, not imitation of you and your voice, or any other singers voice. How many voices have I seen go down to ruin by attempting to imitate the great Caruso or Édouard de Reszké, or Lilli Lehmann or Nordica, or others. Great singers have their faults, too, and the Caruso “gulp” or “souffler” of a note has brought many a tenor to grief. This is only a trick of the breath with him, also a means of dramatic expression, and at times was not good or fitting. So the great Édouard could “raise the roof” with his stentorian “open” tones, and many bassos broke their voices emulating him. So others try to imitate this suave dark round tone of the great Plançon, only to make their own voices lacking in ring and carrying power, until the range were shortened and the voice rendered gloomy and dark. “Oh, wad some power the giftie gie us to ‘hear’ oursels as ithers ‘hear’ us.”

Witherspoon, Herbert. “Singing.” New York: G Schirmer (1925).