Our dog is ill and I feel like a parent again.

We’ve been twice to veterinary physicians, and each time, I watched a kind, knowledgeable human being gently examine a living thing that is both more than, and not quite, our child.

Our dog is old enough to be middle-aged, but she can’t tell us how she feels or what might be wrong. We can only look at her eyes, watch her tremble, mop up the vomit, toss away the food she won’t eat, and pray that she doesn’t become any worse.

With both sons grown, educated, employed and debt-free, I never thought the disquieting, uneasy realization would return.

As my wife and I took turns holding her, we each revisited the truth that, no matter how many doctors you see, how many miracle drugs you have in your medicine cabinet, and how carefully and lovingly you’ve nurtured your child, all life is precious, fragile and prone to suffering for which there may be no identifiable cause, definitive explanation, or optimistic prognosis.

You hold this warm being that, just a few hours previously, seemed content, even happy, to be with you. You went on walks together. You stood patiently as she sniffed here and there. You held the leash and explained that we weren’t going to chase squirrels right now. When you saw another dog and heard no growls, you let them sniff each other. When she relieved herself, you picked up the solid matter with a special bag and put it in its special place and said to yourself that, despite the truly horrible stuff in your morning newspaper, the yammering “panel of experts” in your evening newscast, the vagaries of the stock market, how much you were charged to fix the car, and the predictably marvelous way tax cuts only make your taxes go up, all was right in your world.

I even joked about it. While other people bragged to us about fancy cruises, new kitchens, sons and daughters acquiring jobs, promotions, engagements and other rights of passage, I quietly told myself that today I had a nice walk with the dog. What could be better?

Now all that seems a wispy dream, a false innocence fashioned from a willingness to forget the fretful wisdom of parenthood.

I put the dog in her harness, carried her down the steps and placed her gently in one of her favorite sniffy places. She stood trembling, so weak she couldn’t move. I brought her back in, hoping that this was this a side effect of the medication the vet prescribed, or the illness’s nadir, after which her health and spirit would return so she could chase the squirrels off our deck and bark at neighborhood dogs that had the audacity to pass by.

She fell asleep and I didn’t hear her snore or flutter her paws as in her dreams. She does not move and her breath is shallow.

And I fret and worry, clinging to the discomforting fact that my wife and I have done everything right. We’ve been to two vets. Tests were taken, and two x-rays. We were giving medicine and showed how to administer it. We can only wait, knowing from experience that doing everything right is no protection against loss, illness, reversals and the bad luck that happens often enough so that it seems the only difference between a suffering dog and another running after a stick on an open field is–good luck.

And time, which doesn’t heal all wounds but can, occasionally, provide the space to make them go away.

Until we have to be lucky again.