Persons who gamble in Exchange Alley, by pretending to buy and sell the public funds, but in reality only betting that they will be at a certain price, at a particular time; possessing neither the stock pretended to be sold, nor money sufficient to make good the payments for which they contract: these gentlemen are known under the different appellations of bulls, bears, and lame ducks.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Stock Drawers * Stomach WormNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes