I came up with two variations on the same idea.  Which do you think works better?

 “Your disease,” said the naturopath,
“Is provoked by an excess of wrath.
“There's a cure, though, (you're lucky):
“Just sing to your duckie
“Each night as you soak in the bath.”


“Thy disease,”  said the naturopath,
“Will respond to a mineral bath.
“If thou wield'st, as a scrubber,
“A fowl made of rubber.
“Hath thy bathtub a duckie?” “It hath.”

Based on the suggestion: “naturopath”