Historicism/New Historicism/Holocaust Party

I enjoyed reading The Holocaust Party because it was nothing like I have read before. It kept my attention and I think the story had a rather interesting ending. I found it quite interesting how Mrs. Isabel seemed so harmless and pure until she made that comment about "The Blood Test". I still am not sure what she meant by that. She made a statement about the Jews having thinner blood than normal blood. What kind of thing is that to say. I also wondered why she waited until it was just her and Joel in the room to say what she said. I also found the father's character to be kind of interesting. It seemed as though he could not keep still. I wished the author would have said a little more about him.