From an enquiry in the OED on the word “savage” I was led to a line from The Merchant of Venice, which in turn led me to the broader context in Act V of the play. Here is a delightful part of Act V, sc. i about the effects of music.
The image above is from this edition, which exhibits such fine typography that I thought it worth giving as such, rather than retyping it; the same text can be found in the original-spelling edition from Oxford, p. 506, and here it is in modernized orthography (from here):
I am never merry when I hear sweet music.
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 turn’d to a modest gaze
By the sweet power of music: therefore the poet
Did feign that Orpheus drew trees, stones and floods;
Since nought 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.
I don’t know that this is one of the better known parts of the play, but it deserves to be.