chapter 48 what is the hippocratic oath?

The Hippocratic Oath was written by Hippocrates is still held sacred by physicians: to treat the ill to the best of one's ability. The oath was basically not to cause harm to anyone:

"That's the difference between us and them," Maddy said. "After Az and I found out what the operation really meant, we realized we'd been party to something horrible. People had had their minds changed without their knowledge. As doctors, we took an ancient oath never to do anything like that."