A letter addressed to anatomy students at the University of California, Irvine, went viral on Facebook this past March. A man named Tony Barrett had willed his body to the UCI Medical School after a long battle with ALS and he wanted to introduce himself to the anatomy students who would be dissecting him. Before his death, Tony shared his letter on Twitter:

“My name is Tony and I’ll be your practice cadaver. I sincerely hope my body helps you to become a great doctor. I hope I have helped you to pursue your passion. The world needs great doctors, and I have no doubt that you’ll be one. Now let’s get to work! Pick up that #10 blade and let’s explore this together.”

Sacrificing your body to science as Tony did is one of the greatest gifts you can give. However, the tradition of body donation for medical research and teaching has had a less-than-pristine past. It’s filled with many gruesome stories like grave-robbing, black market deals and even murder. New research in the book Bioarchaeological Analyses and Bodies, including a study that I authored, adds to that history. Anatomists in early 20th century Manhattan seem to have capitalized on emerging racial segregation in the post–Civil War era in an attempt to acquire more bodies for research.

In the 17th and 18th centuries, it was fairly common for “resurrection men” to dig up recent graves and steal the bodies therein in order to sell them to nearby medical schools. It was, that is, until a curious child peeked into the anatomical theater window at Columbia University and discovered his own recently deceased mother on the dissection table. This moment of curiosity sparked the Doctor’s Riot of 1788, where angry New Yorkers dragged physicians and medical students into the streets to answer for the body’s theft.

In response to the riot, anatomists reframed dissection as a way to “save” those people who were otherwise socially irredeemable. If you committed a crime serious enough to draw a death penalty, you might be seen as useless to society, but at least your body could be of service after execution. Tactics shifted again, though, when America’s growing medical field demanded more bodies than death row could provide. Instead, anatomists helped draft legislation that would incentivize body donation from families who were too poor to afford burial.

But even this wasn’t enough. Reports in the Evening World from 1914 told of hospital staff sitting with poor families and bullying them into handing over family members’ bodies at the moment of death. Implicit in this history of cadaver acquisition is the assumption that those targeted were society’s most downtrodden. As a biocultural anthropologist, I wanted a more nuanced understanding. What other factors may have intersected to increase your risk of ending up on the dissecting table?

To investigate, I examined hundreds of skeletons and their accompanying census records that make up the George S. Huntington Anatomical collection at the National Museum of Natural History in Washington, D.C. These skeletons are all that remain of the New Yorkers processed through the anatomy labs at Columbia University’s College of Physician and Surgeons at the turn of the 20th century.

If New York’s cadaver laws truly took the impoverished indiscriminately, we would expect most of the bodies to come from the poorest neighborhoods. When we mapped the bodies to their owners’ last address, it was clear that many of the bodies of poor blacks and whites alike came from those neighborhoods where black racial segregation was highest. Common sense might not see this as odd; after all, racially segregated neighborhoods in our own time have come to be associated with high rates of poverty.

But when overall neighborhood income was factored in, things became more complicated. The most segregated black neighborhoods were actually economically heterogeneous. In addition, bodies of poor whites not coming from neighborhoods with high black racial segregation came from neighborhoods where poor whites were the exclusive population (like the infamous Five Points district). Even more intriguing is that there were racially mixed areas near wealthy white neighborhoods where the bodies of poor blacks were acquired and yet absolutely no poor whites. So how do we explain these odd correlations?

It seems that the compounding factors of race and poverty in your neighborhood intersected to increase your chances of cadaverhood. Poor whites, though in theory a target for selection, may have been buffered against it if they lived near wealthy whites. Poor blacks, however, had no such protection regardless of where they lived. This lines up with other narratives suggesting black Americans have long been the primary targets of anatomists. My examinations of the skeletal remains themselves support these findings. Compared to the entire city’s demographics, blacks in the collection are overrepresented by a factor of six.

Research by two other biological anthropologists, Aja Lans and Rachel Watkins , suggests that this dissection of black bodies by white doctors simultaneously bolstered the white physicians’ reputations while also dehumanizing their black subjects. After all, it was common practice at this time for white medical students to send postcards home of themselves posing with dissected black corpses propped in the most undignified of positions.

With so many of these skeletons still populating our university and hospital collections, perhaps it’s time to go back into the archives and reflect on how we acquired them in the first place. We may never know their stories the way we know Tony’s, but it’s about time that we at least try.