Mr. White's first wish was interrupted by Morris. What was it, and why was he stopped?

Mr. White was first going to wish for "four pairs of hands" for his wife. We can infer that Morris was alarmed because he thought the wish would come true. He stops Mr. White and cautions him to wish for something sensible.

"Sounds like the 'Arabian Nights'", said Mrs. White, as she rose and began to set the supper. "Don't you think you might wish for four pairs of hands for me."
Her husband drew the talisman from his pocket, and all three burst into laughter as the Seargent-Major, with a look of alarm on his face, caught him by the arm.
"If you must wish," he said gruffly, "Wish for something sensible."