"The old man went to the barn, To get some corn to fed some pigs." A pig is lying on the ground. The old man tries to revive it. The pig jumps on him. Sister Sal brings camphor to revive him. "He has never been to feed them hogs since."
Camphor -- C(10)H(16)O -- is the characteristic component of mothballs. It thus can be used both to revive a person (in small quantities) and to hurt animals (usually in larger doses). - RBW