What was the reaction of Washington Otis on seeing the blood stain? What happened when the blood stain was removed?(CHAPTER 1)

Washington Otis was far from scared and considered it to be all nonsense. He commented that Pinkerton's Champion Stain Remover and Paragon Detergent would clean up the stain and fell upon his knees, rapidly scouring the floor with a small stick of black cosmetic-like substance. In a few moments, there was no stain of the blood stain left on the floor. Washington Otis exclaimed triumphantly that he knew Pinkerton would do it but no sooner had he said those words than a terrible flash of lightning lit up the sombre room. A fearful peal of thunder made them all start to their feet and Mrs. Umney fainted.