An interesting speech from The Merchant of Venice by William Shakespeare:
The reason is your spirits are attentive,
For do but note a wild and wanton herd
Or race of youthful and unhandled colts,
Fetching mad bounds, bellowing and neighing loud,
Which is the hot condition of their blood,
If they but hear perchance a trumpet sound,
Or any air of music touch their ears,
You shall perceive them make a mutual stand,
Their savage eyes turned to a modest gaze
By the sweet power of music. Therefore the poet
Did feign that Orpheus drew trees, stones, and floods,
Since naught so stockish, hard, and full of rage
But music for the time doth change his nature.
The man that hath no music in himself,
Nor is not moved with concord of sweet sounds,
Is fit for treasons, stratagems, and spoils.
The motions of his spirit are dull as night,
And his affections dark as Erebus.
Let no such man be trusted. Mark the music.
Who do we know that has no music in himself and is therefore fit only for treasons, stratagems, and spoils … as dull as night and not to be trusted?
Chug-a-rum! Chug-a-rum! Chug-a-rum!