I don't know what the guy in this Coke ad from 1907 is looking at, perhaps checking if anyone is around before licking out the glass. Or maybe he's ashamed of being a coke addict. Who knows? I love how Coca~Cola will "Quench your thirst and put vim and go into your tired brain ad body". There's a word that has fallen out of the vernacular... vim. I remember my grandmother sometimes using vim & vigor but she had to be the last one I remember doing so. Even myself, Captain Vintage Vernacular, never uses vim... although that can change in the near future.
The original recipe for Coca~Cola involved using cocoa leaves imported from Peru. There was enough of a cocaine amount to give drinkers a buzz.1 By 1903, pressure from the FDA forced coke to change their recipe, using denatured cocoa leaves instead. Although there was a minute amount of cocaine alkaloids left it wasn't enough to give a buzz, caffeine being used for that purpose instead. Indeed, by the time this ad ran, caffeine was the buzz bringer in coke and they used greater amounts than what is present in modern coke formula.2
Alas, Coca~Cola in the USA is only a shadow of it's former self, having been given over to the use of chemical flavorants and sweetened with High Fructose Corn Syrup. The taste is insipid to me, even before I lived in the Philippines and drank "real" Coke. Thankfully though, Mexican coke has made a grand appearance on store shelves across the country. Coming in real glass bottles and made with an older formula that uses sugar, it has a depth of flavor unmatched my US production Coke.3 There's a great website called WhereToFindMexicanCoke.com where you can locate stores near you that carry it. The website is reliant on users to add stores in their area to the map, so it's a work in progress. Check out any ethnic markets in your area and you'll probably find it, I spend $1.39/355ml bottle but between my wife and myself we only consume about 5-6 bottles a week. It's very rich and satisfying stuff so you don't need to guzzle it by the 55gal drum.
1) Wikipedia - Coca Cola Formula
2) Snopes - Cocaine in Coca Cola
3) Wikipedia - Mexican Coke