TL-191: Filling the Gaps

OTL America has a long and sordid history of unethical human experimentation and exploitation on the grounds of "scientific discovery", often on the poor, racial minorities, or prisoners. There's no reason not to think that wouldn't continue in a world where the CSA continued to exist or even become far worse when white supremacy and anti-black racism become explicit state policy. It's not hard to imagine a 191 equivalent of the Tuskegee Syphilis Experiment being far more common and far far worse
One minor butterfly - chiropractic either wouldn't exist, or it'd be very obscure. The founder of chiropractic was a Canadian, who moved to the US after the Civil War. Since UK-US relations would be much worse in TL191 than OTL, he might remain in Canada, and given how much smaller Canada's population is than America's, he'd likely find only a small audience. And after America conquered Canada during GW1, I doubt many Americans would be interested in some weird Canadian alternative medicine.