Here's what Straight Dope has to say:
http://www.straightdope.com/mailbag/mrx.html

Incidentally, I'm reminded of a Puerto Rico guy in my class getting bullshit when lecturer said in South America, the sign for pharmacy was a big "606". The symbol for salvarsan, the first cure for syphilis. (Because it was the six hundred and sixth compound in a series of formulas
Paul Ehrlich had tested for treatment of infedctions. A Jap student of his named Kitasato, discovered it would cure rabbit syphilis. But he never got any credit, so far as I know. Everybody thinks Paul Ehrlich was the discoverer. I read a book by Paul Ehrlich's ex-secretary, who said Paul Ehrlich didn't even want the Jap in his lab, and had him retest all previous formulas that he had found to have no value,just to get the Jap out of his way. But the Jap was the first person able to infect babbits with syphilis. But he didn't get the Nobel Prize.