Two years ago, Roger Galvin, an assistant Montgomery County state's attorney, prosecuted a Silver Spring research scientist on cruelty to animals charges. Today Galvin, 38, acknowledges that the case had a profound effect on his life.

As a result of that single prosecution and extensive reading, he said last week, he is preparing to open a law practice devoted to animal rights cases and work as a public defender on death penalty cases.

The 1982 case, in which Dr. Edward Taub was accused of mistreating monkeys he was using in research on the treatment of stroke victims, focused national attention on the animal rights movement. Galvin obtained Taub's conviction, but it was overturned by the Maryland Court of Appeals.

Galvin has given up eating meat, eggs, fish and milk, and he no longer wears items made of leather. He said he believes animals are treated unethically while alive and slaughtered for food and products that humans do not need.

He founded the Washington chapter of Attorneys for Animal Rights. Earlier this month he was elected vice president of the national organization, which is made up of about 150 attorneys devoted to fighting for the rights of animals.

At the end of this month, Galvin will leave the county prosecutor's office, where he has worked for eight years, to fight death penalty cases as an assistant Maryland public defender. Formerly a supporter of the death penalty, Galvin said reverence for life is "the bedrock" of the animal rights movement -- and that while he could hardly try to protect all animals, he could try to avert the death penalty for those convicted in Maryland of murder with aggravating circumstances.

He said he also plans to open a limited law practice devoted exclusively to animal rights.

Fifteen of the 17 monkeys involved in Taub's research are still alive at a National Institutes of Health facility in Poolesville. Galvin said he visits them about once a month and that he and other animal rights activists recently bought them a television to help stave off boredom.