Twelfth Night - a textual problem

The opening lines of Shakespeare's Twelfth Night read:

If music be the food of love, play on;

Give me excess of it, that, surfeiting,

The appetite may sicken, and so die.

That strain again! it had a dying fall:

O, it came o'er my ear like the sweet sound,

That breathes upon a bank of violets,

Stealing and giving odour!

Alexander Pope emended the word sound (line 5) to south.

A discussion of Pope's motive for this emendation is discussed here:

• http://www.geocities.com/Sebastjan60/English/sound_south.html