It should be noted that the author has established that only the owner of the paw can make a wish with it. He has also established that only three persons can own it and Mr. White is the last. This prevents Mrs. White from using the magical paw herself. Mr. White's ownership of the paw is explained in the following dialogue.
"Did you give him anything for it, father?" inquired Mrs. White, regarding her husband closely.
"A trifle," said he, colouring slightly. "He didn't want it, but I made him take it. And he pressed me again to throw it away."
So neither Herbert nor Mrs. White can use the paw to make a wish. This fact in itself will cause minor and major conflicts. It should also focus the reader's attention and forestall such questions as, "Why doesn't Herbert make a wish?" and "Why doesn't Mrs. White use the paw herself instead of forcing her husband to make a wish against his will?