Thought correctly, I might add.
Uh, no. Transmission rates are higher with anal sex, but not 0 for vaginal sex.
I doubt it was more dangerous than getting AIDS was back then. Yes. That's clearly not the point of that comment, which was saying that making an equivalence between that in syphilis and HIV is not accurate. Unless you're trying to say the mortality rate between HIV was lower than syphilis back then, which seems to be not accurate
A post from Gregory Cochran's and Henry Harpending's excellent blog West Hunter.
The commenter Ron Pavellas adds:
The Wasserman Test.