Why did Major Morris tell the Whites to throw the paw in the fire? Why did Mr. White grab it out?

Major Morris already knows the way the Monkey's Paw works as he has seen the results of making wishes on it. He saw the first man wish for death with his third wish and he is open about his desire that he'd never seen it. He "solemnly" tells Mr. White that he "better let it burn." Once Mr. White snatches it out of the fire, Major Morris again suggests that he ought to "pitch it...

Major Morris already knows the way the Monkey's Paw works as he has seen the results of making wishes on it. He saw the first man wish for death with his third wish and he is open about his desire that he'd never seen it. He "solemnly" tells Mr. White that he "better let it burn." Once Mr. White snatches it out of the fire, Major Morris again suggests that he ought to "pitch it on the fire like a sensible man."

But Mr. White has not seen these consequences first hand. He cannot understand the terror that awaits and feels more of what his wife does about how it seems like "Arabian Nights," something exciting with great possibility. Despite the fact that he has "all [he] want[s]," he cannot throw away the opportunity the paw represents. He even recounts that Major Morris told him a third time that he ought to throw it away before he left but Mr. White simply couldn't do it.