ring the listening to vocal tones.

A peculiarity of the laryngeal adjustments accompanying the listening to
voices is seen in the fact that the possession of a fine or well-trained
voice is not required in this process. It does not matter whether the
physical organs are capable of producing fine musical tones. The
nervous equipment alone is involved; this is frequently highly
developed, even though the physical voice is very poor. A keen and
highly-trained ear is the only requisite. Players in the opera
orchestras often develop this faculty to a high degree, even though they
may never attempt to sing a note.

_Muscular Sense_

An exhaustive analysis of the various classes of sensations, commonly
grouped under the general heading of muscular sense, would involve a
mass of technicalities not necessary to the present purpose. It is
sufficient to bear in mind the limitations of this sense, and to notice
what it tells us, and what it does not tell.

Through the exercise of the muscular sense we are informed of the
movements, positions, and conditions of the different parts of the body.
Of specific muscular contractions very little information is conveyed.
Thus, when the arm is bent at the elbow the muscular sensations of the
movement are clear and definite; but, under normal conditions, these
sensations do not inform us that the movement results from the
contraction of the biceps muscle. Knowledge of the muscular structure
of the body is not involved in muscular sense. The muscular sensations
of bending the arm are felt in precisely the same way by the professor
of anatomy and the ignorant child.

Further, no amount of attention paid to muscular sensations will inform
us exactly what muscles are contracted in any complex action. A single
stroke in the game of tennis, returning a swift service for example, may
involve some contraction of every muscle of the entire body. A skilful
player may observe with the utmost care the muscular sensations
accompanying this stroke; he would never be able to learn from these
sensations whether the number of muscles in his forearm is ten or one
hundred.

For the same reason the sympathetic sensations of tone tell us nothing
whatever of the muscular structure of the vocal organs. When listening
to a throaty voice, we feel that the singer's throat is tightened,
stiffened, or contracted. But no matter how keen and vivid this
sensation may be, it leaves us in complete ignorance of the na