I just looked up blue-tail fly, and the notes sujest that cracked corn might be refering to wiskey. While that coule be, I wounder if it might mean corn that isn't soft enough to eat whole so its cracked up and used as slave rations, since it would be cheap, and although they couldn't have known, it's a lousy source of protein and hinders brain development if thats all you have to eat. I wounder how it got to be comon to use jimmie crack corn.