Despite being in a scientific field, men in earlier times were still motivated to document their findings in line with their predjudices at the time. If science could not explain anatomy or evolution, then junk science was allowed to enter the arena and the unexplained was attributed to race or the inferiority of all races to whites.
This is a good example of discourse communities being closed off to new ideas. Despite an established discourse community, scientists at the time were subject to the pitfalls of the time.