"The thing was troubling her - something she had overheard several men say about her when they thought she was the last person in the world within hearing distance.
"So she had asked two of her friends. They were amazed that she had never thought of this sort of thing before. But they were frank enough to explain it to her in a delicate way. And she never ceased being grateful to them.
"That's the insidious thing about halitosis (unpleasant breath). You, yourself, rarely know when you have it."
Ad for Listerine, 1924.