One of the most surprising things I learned in law school was the legal definition of "battery." Police and news programs often mention the terms "assault and battery." When you hear that, you might form a mental picture of some punk beating up an upstanding citizen who said or did something the loser didn't like.

In reality, battery can be a much more subtle act. It can mean simply committing a physical act to or upon someone without their express consent. When a professional boxer bashes Mike Tyson in the ring, it isn't battery because consent is present. On the other hand, if a plastic surgeon removes a mole from your nose while you are under anesthesia for an eyelid job, he has committed actionable battery unless express consent for removing the mole was obtained prior to sedation.

A similar principle applies to the veterinarian who performs an act upon an animal without the permission of its owner. That's potentially actionable (lawsuit-generating), and the potential exists for a malpractice accusation.

But what about procedures with more permanent results? You wouldn't neuter an animal without written authorization. An amputation without the advance approval of the person who brought you the pet would be out of the question. Without that signed form, forget about undertaking a euthanasia.

These questions aren't even a challenge.

Consider, though, where you would stand if you committed a "pet battery" (performed an irreversible procedure) on an animal that belonged to a party other than the one who brought the animal in for treatment?

If you have been in practice very long, you know how this issue would most likely arise: Negligent owner leaves dog outside, and it becomes sick and fly-bitten. Samaritan neighbor scarfs the pet up during the day, gets it treated and returns the animal before anybody knows it is missing. No harm done, probably even if something happened to the animal at your practice, because the Samaritan signed a form saying he or she was the owner or the owner's authorized agent.

Now, though, consider a potentially more problematic situation: Jerry and John always come in together with Fluffy. Lately, though, Fluffy has been declining in health and her condition is serious enough that euthanasia would not be out of the question. One afternoon, Jerry comes in and signs for Fluffy's euthanasia, which you perform.

But when John gets home from work and finds out what happened, he is outraged. He calls and tells you he plans to sue you and Jerry and contact the state board. It seems that the true owner, John, would never have considered euthanasia, and Fluffy has been John's property ever since birth and well before Jerry and John got married.

Now the marriage is on the rocks, and you are caught between a rock and a hard place.

The general law of personal property probably would have been dispositive of this potential issue back when animals were considered personal property and nothing more. Now, however, in a world where domestic animals are being left (and are receiving) millions in testamentary bequests and are generating lawsuits and substantial pain-and-suffering verdicts, we veterinarians don't dare be so cavalier where treatment authorization is concerned.

Consider this example from one of my own veterinary practices:

We had been treating a certain feline for almost 20 years. Originally it was brought in for kitten shots by the female owner (W) and then from time to time as an adult cat by her new husband (H).

When the cat became ancient, H brought kitty in for euthanasia. It seemed odd to me that he arrived in the middle of the day and without his wife. I examined the cat, agreed that euthanasia would be a realistic alternative and H signed the papers. After he left, I thought harder about the situation and told my staff to put the euthanasia on hold; I wanted to wait on this one for at least a day.

Sure enough, the inevitable spousal battle ensued when W got home from work.