Why does Morris grow pale after he makes his thrid wish in "The Monkey's Paw"?i just want to know the answer.

Author W. W. Jacobs never tells the reader why
Sergeant-Major Morris turned pale while discussing his third wish in "The Monkey's
Paw." The result of his third wish could not have been a happy one,
however.

   
"Well, why don't you have three, sir?" said Herbert White, cleverly.
    The
soldier regarded him in the way that middle age is wont to regard presumptuous youth. "I
have," he said, quietly, and his blotchy face whitened.
    "And did you
really have the three wishes granted?" asked Mrs. White.
    "I did," said the
sergeant-major, and his glass tapped against his strong
teeth.

Later, the Whites used
their own third wish to erase the aftermath of their second wish. Mr. White "frantically
breathed" as he made it, and Mrs. White gave "a long loud wail of disappointment and
misery" when she felt only "a cold wind" and saw nothing but a "deserted road"
outside.