Debates about using animals in research stretch back centuries, but the modern animal rights movement was born in 1975 when philosopher Peter Singer, the Ira W. DeCamp Professor of Bioethics at Princeton, published his book “Animal Liberation.”

Often called the “bible” of the animal liberation movement, the book calls for the end of animal use in medical research.

Adrian Morrison, professor emeritus of behavioral neuroscience at Penn Vet, has long advocated for the humane use of animals in research and says human beings’ first duty in terms of research is to fellow human beings.

The opposing sides have clashed often over the past three decades, sometimes violently. Morrison details this conflict and what he believes are its causes in his new book, “An Odyssey with Animals: A Veterinarian’s Reflections on the Animals Rights & Welfare Debate.”

Morrison says “a very negative series of events” led him to write the book. After testifying for neuroscientist Edward Taub in the Silver Spring Monkey Case in the early 1980s and publicly defending scientist John Oren’s research on cats, Morrison became Public Enemy No. 1 in the animal rights community. In January of 1990, his Penn laboratory was raided and vandalized by the Animal Liberation Front, a group the FBI has called “one of the most active extremist elements in the United States.”

After the break-in, Morrison says PETA cofounder Ingrid Newkirk told The Village Voice: “PETA intends to use Morrison to persuade other vivisectors who were heartened by his strong stand on animal research that it doesn’t pay off.”

Morrison says also he received death threats and hate mail. One envelope contained a bloodstained condom allegedly tainted with HIV-infected blood.

Morrison (removed “says he”) can greatly sympathize with people who are concerned about how humans treat animals. As an animal lover (he has a cat named Buster), he deplores dog fighting, cockfighting and bullfighting. But he says animal rights activists who break into laboratories go too far (removed “he says”).

“Society couldn’t hold together if we could all go off and express ourselves that way,” he says.

If animals were no longer used in research, Morrison says there would be “serious” consequences.

“To know how a drug works, for example, for developing a new drug that’s in a living organism, you have to make sure that, No. 1, it’s safe for all the organs of the body, and also that it actually does what you’re proposing that it does before it’s then tested on human volunteers,” he says. “Would you, for example, want to take a medicine that was given to you without any indication that it’s been shown to be safe in a living being?”

Animals benefit too from animal research, he says. “People don’t necessarily think about that, that their cat or dog that they love … is protected from various awful diseases by the work that’s been done by medical researchers on viruses, developing the vaccines.” H1N1, or swine flu, and rabies are two examples of diseases that inflict both animals and humans.

Safeguards are in place at Penn to ensure that animals are treated humanely in research. Penn researchers are governed by two laws administered by the Public Health Service and United States Department of Agriculture. The USDA also inspects University facilities.

As society has evolved in its thinking about animals, Morrison says more and more people are realizing the need to take a larger role in the study of animal welfare, for animal welfare’s sake.

“We have [animal welfare] student organizations that are terrific,” he says. “They have great programs going beyond medical research, [such as] using animals in agriculture.”

Morrison says the most militant animal rightists cannot be reasoned with, but he’s confidant that if others are educated about research on animals, they will recognize it is essential for human safety.

“Anybody who doesn’t believe that animals should be used is morally obligated to participate in clinical trials,” he says.