I find that early recipes for Whisky Sours, and other types of sours, do not
use eggwhite. Drinks with eggwhite, or eggyolk, are usually prefixed by Silver
or Golden respectively.
The eggwhite does create a foam that looks good, but it is not a default in a
Whisky Sour. Another addition to a Sour is Angostura Bitters. Yes, some people
say it improves the drink, but is it a default ingredient? No it isn't.
Also a cherry is not a default garnish for a Whisky Sour, but lots of people
think it is. Personally, a lemon slice is much better.
Cheers!
George S.
"You have your way. I have my way. As for the right way, the correct way, and
the only way, it does not exist." - F. Nietzsche
"innovation distinguishes between a leader and a follower" - Steve Jobs