Green’s Dictionary of Slang

musical adj.

used of a horse that suffers from respiratory problems.

[UK]‘Doss Chiderdoss’ ‘When They Sigh’ Sporting Times 15 Feb. 1/3: But the cab-horse was a roarer, and the slowest of blood-stock, / And the fare said to the cabby, ‘That’s a musical old crock!’.

In compounds

musical fruit (n.) (also music fruit, musicos)

any fruit or vegetables, esp. beans or Jerusalem artichokes, that produce flatulence.

[US]G.W. Small Story of the 47th 75: We played marbles on the deck with ‘music fruit’ and rolled our eyes around like a dying calf when we lost our ‘stake’ [HDAS].
[US]A. Halper Foundry 172: BEANS! That Musical Fruit!
[US]A.J. Pollock Und. Speaks n.p.: Musicos, beans.
[US](con. 1940s) G. Mandel Wax Boom 125: Somebody farted. Men laughed [...] ‘Beans, beans, the music fruit, the more you eat the more you toot.’.
[US]Sanford and Son [NBC-TV] Beans, beans, the musical fruit [HDAS].
[Can]M. Atwood Cat’s Eye (1989) 125: Pork and beans the musical fruit, the more you eat, the more you toot.
[UK]R. Ehrlich ‘The knowledge’ Guardian 9 Sept. [Internet] Beans, beans, the musical fruit. Simmered at great length with bacon, herbs, and tons of garlic.