By chance I ran across an 2009 post by Rachel Martin of NYU Museum Studies, which investigates a mystery related to one of my scientific heroes, Franz Weidenreich ("A Hittite Goddess and Theories of Race):
In the archives of the American Museum of Natural History, there is a lantern slide. It shows a head carved in stone from an archaeological excavation. This image presented me with several mysteries. I not only had to identify the subject, but also the reason why the slide was at AMNH. When I first saw the slide and its box, I thought the image had been used in eugenics lectures. Now, however, I believe the reverse is true. The slide’s owner was actually a strong opponent of eugenics. I believe that he used the slide in lectures arguing against the practice of eugenics in anthropological research.
She doesn't have an answer at the end, but I bet there's a story here someone could uncover more fully.