I should have taken her to the vet weeks ago. She's been dragging around for at least that long, her gait a little slower these days, her eyes a little less bright. I notice these things, but I ignore them. I sit on the floor and scratch her ears and pat her head and say, "How's my puppy?" And she sighs and wags her tail, the way she has always done. I see that the hair under her chin is more white than black and that there are tufts of white under her belly and that…