Are you talking about syphilis or Salversan? (snicker) Salversan can turn the skin blue. Ironic we used to use a variant of Salversan to treat dogs for heartworms. It was a combination of arsenic derivatives.
Yikes for the dogs. A. Heartworms B. Arsenic.
Choose A or B.
I’m reminded to make sure my zoggies heartworm pills are up to prescription