In this past weekend's Wall Street Journal, Eric Felten looks at Rock and Rye, a supposedly-medicinal pre-mixed cocktail. I was just starting to look into the history of the Rock and Rye when Greg Lindgren of the bar Rye in San Francisco send me some information about it, but now Greg's concoction is mentioned here and Felten did my research for me. Thanks!
At Rye in SF, they serve a Rock and Rye Manhattan and in the winter use it in a Hot Toddy.
One thing that Lindgren mentioned is that he thought Southern Comfort might have been a Rock and Rye in the beginning. I checked with Sean Wachsmand, PR Manager of Southern Comfort about this. He got back to me:
Heron (Southern Comfort's inventor) was obviously making a cocktail at first and did not include any digestif herbs in his recipe. He used honey as a sweetener."
So there you have it. Southern Comfort was probably not meant to be medicine, but if you take it as a shot with lime juice, it'll combat scurvy anyway.