Pain-killer
Pain-killer is a patent medicine that enters the story as Aunt Polly's latest remedy for Tom Sawyer's mysterious low spirits. She is an inveterate experimenter with health fads, subscribing to quack periodicals and buying every new cure-all that appears. When Tom grows indifferent to her usual water treatments and oatmeal diets, she hears of Pain-killer for the first time, orders a lot, and tastes it herself, finding it to be "simply fire in a liquid form." She immediately drops all other treatments and pins her faith on this new substance.
Administration and the Cat Episode
Aunt Polly gives Tom a teaspoonful of Pain-killer and watches anxiously for the result. The "indifference" is instantly broken up; Tom could not have shown a wilder, heartier interest if she had built a fire under him. Tom soon realizes that this sort of life, while romantic in his blighted condition, has too little sentiment and too much distracting variety. He hits upon the plan of professing to be fond of the medicine, asking for it so often that he becomes a nuisance, and his aunt finally tells him to help himself. She watches the bottle clandestinely and finds that the medicine does diminish, but it does not occur to her that Tom is mending the health of a crack in the sitting-room floor with it.
One day Tom is in the act of dosing the crack when his aunt's yellow cat, Peter, comes along, purring and eying the teaspoon avariciously. Tom warns Peter, but the cat insists, so Tom pries his mouth open and pours down the Pain-killer. Peter springs a couple of yards in the air, delivers a war-whoop, and tears around the room, banging against furniture, upsetting flower-pots, and making general havoc. He then rises on his hind feet and prances around in a frenzy, before tearing through the house again and sailing through the open window, carrying the rest of the flower-pots with him. Aunt Polly enters in time to see the cat's final summerset and exit, and stands petrified with astonishment. Tom lies on the floor expiring with laughter.
Aftermath and Thematic Significance
When Aunt Polly discovers the telltale teaspoon under the bed-valance, she raises Tom by his ear and cracks his head with her thimble. Tom defends himself by saying he did it out of pity for the cat because it had no aunt, who would have "roasted his bowels out of him 'thout any more feeling than if he was a human!" This remark gives Aunt Polly a pang of remorse, putting the matter in a new light: what was cruelty to a cat might be cruelty to a boy, too. She softens, feels sorry, and tells Tom he need not take any more medicine. The episode thus serves as a comic turning point that exposes the harshness underlying Aunt Polly's well-meaning but misguided remedies, and it momentarily shifts the power dynamic between them, as Tom's clever manipulation of the situation forces his aunt to reconsider her methods. The Pain-killer, a patent medicine meant to cure, becomes instead an instrument of chaos and a vehicle for Tom's rebellion, revealing the gap between adult authority and a boy's resourceful defiance.
