She could not describe it, she could not tell just what it was, and yet her sharp mother-instinct seemed to detect it and perceive it.

What if the boy were really not her son, after all?
Oh, absurd! She almost smiled at the idea, spite of her griefs and troubles.

No matter, she found that it was an idea that would not 'down,' but persisted in haunting her.

It pursued her, it harassed her, it clung to her, and refused to be put away or ignored.

At last she perceived that there was not going to be any peace for her until she should devise a test that should prove, clearly and without question, whether this lad was her son or not, and so banish these wearing and worrying doubts.