Burns with a low blue flame: This almost certainly has some relationship to the ancient assertion that if one drank enough rum or brandy and was bled, the blood would burn blue until totally consumed. As early as 1836 this belief was satirized, which probably helped the idea to remain current. “The doctrine of the spontaneous combustion of drunkards has just been exemplified in New York, in the case of a man who had drunk two gallons of rum in five days; he was afterwards bled, and on the application of a match, the blood took light, and burnt blue until it was consumed. Spirit-drinkers should be warned by this, that they may, by possibility ‘flare up’ without bargaining for such a luxury,” read a dispatch published in The Satirist, and the Censor of the Time, March 6, 1836.
DRUNK: The Definitive Drinker’s Dictionary by Paul Dickson