The Mask

never been one to tear up the furniture, not since he was just a kitten,” Grace said. “He’s never been a climber, either. But now, every time I turn around, he’s perched on top of something, peering down at me.”
    Brad examined Ari, feeling for swollen glands and enlarged joints. The cat cooperated docilely, even when Brad used a rectal thermometer on him. “Temperature’s normal.”
    “Something’s wrong,” Grace insisted.
    Aristophanes purred, tolled onto his back, asking for his belly to be rubbed.
    Brad rubbed him and was rewarded with an even louder purr. “Is he off his food?”
    “No,” Grace said. “He stills eats well.”
    “Vomiting?”
    “No.”
    “Diarrhea?”
    “No. He hasn’t shown any symptoms like those. It’s just that he’s… different. He’s not at all like he was. Every symptom I can point to is a symptom of a personality change, not an indication of physical deterioration. Like destroying the pillows. Leaving the mess on the armchair. The sudden interest he’s taken in climbing. And he’s gotten very sneaky lately, always creeping around, hiding from me, watching me when be thinks I don’t see him.”
    “All cats are a bit sneaky,” Brad said, frowning. “That’s the nature of the beast.”
    “Ari didn’t used to sneak,” Grace said. “Not like he’s been doing the last couple of days. And he’s not as friendly as he used to be. The last two days, he hasn’t wanted to be petted or cuddled.”
    Still frowning, Brad lifted his gaze from the cat and met Grace’s eyes. “But dear, look at him.”
    Ari was still on his back, getting his belly rubbed, and clearly relishing all the attention being directed at him. His tail swished back and forth across the steel table. He raised one paw and batted playfully at the doctor’s large, leathery hand.
    Sighing, Grace said, “I know what you’re thinking. I’m an old woman. Old women get funny ideas.”
    “No, no, no. I wasn’t thinking any such thing.”
    “Old women become obsessively attached to their pets because sometimes their pets are the only company they have, their only real friends.”
    “I am perfectly aware that doesn’t apply to you, Grace. Not with all the friends you’ve got in this town. I merely—”
    She smiled and patted his cheek. “Don’t protest too strongly, Brad. I know what’s going through your mind. Some old women are so afraid of losing their pets that they think they see signs of illness where there are none. Your reaction is understandable. It doesn’t offend me. It does frustrate me because I know something is wrong with Ari.”
    Brad looked down at the cat again, continued stroking its belly, and said, “Have you changed his diet in any way?”
    “No. He gets the same brand of cat food, at the same times of day, in the same quantities he’s always gotten it.”
    “Has the company changed the product recently?”
    “How do you mean?”
    “Well, does the package say ‘new, improved,’ or ‘richer flavor,’ or anything like that?”
    She thought about it for a moment, then shook her head. “I don't think so.”
    “Sometimes, when they change a formula, they add a new preservative or a new artificial flavoring or coloring agent, and some pets have an allergic reaction to it.”
    “But wouldn’t that be a physical reaction? Like I said, this seems to be strictly a personality change.”
    Brad nodded. “I’m sure you know food additives can cause behavioral problems in some children. A lot of hyperactive kids calm down when they’re put on a diet free of the major additives. Animals can be affected by these things, too. From what you’ve told me, it sounds like Aristophanes is intermittently hyperactive and may be responding to a subtle change in the formulation of his cat food. Switch him to another brand, wait a week for his system to purge itself of whatever additives have offended it, and he’ll probably be the old Ari again.”
    “If he isn’t?”
    “Then bring him in, leave him with me for a couple of days, and I’ll give him a really thorough going over. But I strongly recommend that we try changing his diet first, before we go to all that trouble and expense.”
    You are humoring me, Grace thought. Just coddling an old lady.
    “Very well,” she said. “I’ll try changing his food. But if he’s still not himself a week from now, I’ll want you to give him a complete battery of tests.”
    “Of course.”
    “I’ll want an answer.”
    On the stainless-steel table, Aristophanes purred, happily twitched his long tail, and looked infuriatingly