How does the shift in the physical description of the landlady throughout the passage impact he storys meaning?

Throughout the passage, the shift in the physical description of the landlady does impact the story's meaning. At first, when you hear what the landlady looks like, you'll think that she's not at all "wrong in the head", but as you progress through the story, the landlady morphs into a detrimental woman. When Billy sees the landlady at the start, he thinks that she " looked exactly like the mother of one’s best school-friend welcoming one into the house to stay for the Christmas holidays (29)". He basically thinks that she's just a kind woman who won't do him any harm. Later, "he caught a whiff of a peculiar smell that seemed to emanate26 directly from her person. It was not in the least unpleasant, and it reminded him — well, he wasn’t quite sure what it reminded him of. Pickled walnuts? New leather? Or was it the corridors of a hospital? (78)". He thought that she was "dotty", but he didn't care, nor does he really pay any close attention to how she acted or looked. All he thought was since she invited him to a place to stay for a good amount of money, she was welcoming and inviting, therefore, he assumed that she was innocent and not at all "wrong in the head". In the beginning, we all thought that this was going to be an innocent story where Billy enters a house and a landlady allows him to stay there. The landlady would mind her own business and be polite and Billy would be safe and just be there for a tiny bit, all happy and everything would be just fine. But no. As the story reveals more, it gets more twisted and dark. The landlady turns out to be purposefully poisoning Billy with tea and probably stuffing him later. All things will turn for a deadly end

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