Green’s Dictionary of Slang

(US) spirit, energy.

1860		J.G. Holland Miss Gilbert’s Career (1870) 239: If you’ll take thunder and lightning and a steamboat and a buzz-saw and mix ’em up and put ’em into a woman, that’s jasm.
1886		Harper’s Mag. Sept. 579/2: Willin’, but hain’t no more jas’m than a dead corn-stalk [DA].