So when your elderly cat develops anorexia, it sometimes means his sense of smell is diminished. The general advice for this kind of finickiness is to feed stinky food.
I'd brought George to the vet for a thyroid re-check; all was well there. Yet he continues to eat very little, and his spine feels like a marimba. The causes could be many, including cancer, but first I thought I'd try a different food. I picked up a good brand of salmon cat food; he ate it voraciously and kept it down. I went back to the store the next day to discover they were out, so I got another fishy food, some ocean thing.
And this is how I confirmed once and for all that George (and Harry, to whom I gave some as a treat) are allergic to ocean fish:
Puking. Projectile, nonstop puking.
Puking on the bedroom floor. Puking on the bathroom floor. Puking on the bed comforter that had been washed all of 12 hours before. Puking on the futon, puking on the kitchen floor. Loud, forceful, splashing puking everywhere except, thank God, the wool floor rug I'd taken a chance on putting down last week.
Puking means no medicine staying down, which means no thyroid control. I did manage to get some down George's throat tonight and he did not puke it up, which was a miracle. Tomorrow, if he shows an interest in food, we're back to chicken. He seems to be feeling better, and I, having gone through more rags in two days that I do in a week, can finally rest.