I was having a beer at Keens Chop House, contemplating the many pricey good items to be had on the bar menu, when I noticed a wire rack loaded with hard-boiled eggs. Being low on cash and long on hunger, I asked, "How much for the eggs?" "They're free," said the barkeep. Ah, free. I'll take an egg, then.
Taverns and saloons 100 years ago may have been rough joints, and you always ran to risk of being Shanghaied or slipped a Mickey. But they provided you with food in some form, so you didn't get completely smashing drunk (or, if you did, it wasn't their fault). Keens' eggs are a throwback by the bygone tradition of the free lunch. Many of the old drinking establishments used to lay out free buffets which were all you can eat. (You'll still find this in some pubs in England.) Men drank, but they could also eat if they chose, without worrying it would chip into their drinking money.
Today, the food you find on most bars is the salty kind: chips, pretzels, etc. As anyone in the bar biz knows, these are not meant to provide sustanance. They're meant to make you thirsty, so you order more liquor.