The old formula that dogs age seven years for every human year has been pretty well debunked. Still, if you follow that formula, my black lab mix, Daphne, and I appear to be in the same age range. She’s 11, I’m 75. You do the math.

Friday, when we visited the vet, I was surprised that Daphne was avoiding contact despite the doctor’s friendly advances.

“Well, she’s never been real friendly toward me,” shrugged the vet, “and she’s getting older. Dog behavior gets more exaggerated as they age. Like people. Haven’t you noticed that as we get …”

“Let’s not go there,” I interrupted before she could say the word “older.”

I don’t know which I struggle with more, my dogs’ mortality or my own. One of my favorite authors, Gary Paulson, has already published the book that I’d like to have written: “My Life in Dog Years.” It’s a memoir, each chapter devoted to a dog that was special in Paulson’s life. I can pretty much tell the story of my own life through the escapades of the dogs I’ve shared it with. In my adult years, there were Mephistopheles (a chihuahua called “Mephi” for short), Pandora, Christy, Becky, Sadie I, Hobo (who was with us for less than twenty-four hours but remains part of my soul), Sadie II, Ben, and now, Daphne and her junior kennel mate, Tawny. I learned valuable lessons from each, and each eventually broke my heart.

Even a shattered heart always has room for another dog. You accept that new puppy or that mongrel stray, knowing that you’re going to go through the cycle all over again: training, sharing, loving, learning, grieving. A few years ago, some friends who were aging refused to get another dog when their beloved springer spaniel died. They dearly missed having a dog, but they were in their eighties. They figured they had such a short life span remaining, it would be unfair to the dog. I fear I could never be that selfless. I must always have a dog, and I’m reconciling myself to the probability that it won’t always be Daphne.

Last summer, one of Daphne’s toes was amputated due to skin cancer, which was fully excised. Now we await lab results for samples taken from a suspicious growth on her leg. The results will take at least a week, said the vet.

“I’m confident it’s not cancer,” I said. The vet looked at me quizzically.

“When Daphne had the cancerous toe,” I explained, “before it was diagnosed and removed, Tawny, the younger dog became uncharacteristically aggressive toward Daphne. His attacks were so outrageous I began looking for a new home for him. Once the cancer was gone, Tawny was back to his playful relationship with the older dog.”

“Isn’t that weird,” responded the vet.

Weird, yes. But this time around, Tawny hasn’t displayed an ounce of aggression toward Daphne. I’m going with Tawny’s prognosis. It makes waiting for lab results less anxiety producing.