In Medical Apartheid (Reviews, Sept. 25), Harriet Washington offers a shocking account of African-Americans exploited for medical research.

Racism, of course, plays a part in the exploitation you describe, but are there other causes?

The more research I did, the more it became clear to me that there was a terrible confluence of factors. Racism created a set of circumstances—particularly poverty and class status—that made black people vulnerable. But we ask how well-meaning, beneficent doctors could do such inhumane procedures. The answer is: because they could. Experimenting on African-Americans was accepted. It was established practice and simply wasn't questioned. Reading old Southern medical journals,... these doctors... are astonishingly frank in their belief that black people were less than fully human. It's not that there weren't rules—some states had clear rules for consent in 1887, but they were not federally enacted until much later.

How were you affected, as a person and as a scholar, by uncovering these stories?

When I first began doing this work, I wanted to be "professional," and I prided myself on not reacting too emotionally to the horrible things I was reading. But one day I was on the train to Boston reading reports by Orlando Andy, M.D., head of the Department of Neurosurgery at the University of Mississippi, about removing parts of the brain of nine-year-old black boys during autopsies in the early 1960s. His tone was so passive and objective, and he was so proud of his work, that I just started to cry. I had tried to maintain objectivity, but was then pleased to see I couldn't be simply objective. This is not what the material called for. From then on I would write a chapter and then go back to it months later to make sure that it was both "objective" and empathetic.

What effect do you hope your book will have?

I hope the revelations will improve human experimentation policies in this country, especially our weak Institutional Review Board system and the recent erosion of informed-consent laws. I also hope that the book will help to change African-Americans' behaviors. A steady diet of denials and dismissals has encouraged rather than assuaged their fears, so the book's candor is a necessary prerequisite to asking them to participate in safe, ethical medical experimentation.