 And then after it was over, Thomas Francis stood up on the podium at Rackham Hall at the University of Michigan and said, safe, potent, and effective. That's what he said. Those three words were the headline of every major newspaper in this country. I mean, church bells rang, synagogues and churches held special prayer meetings. Department stores stopped, trials stopped, you know, so the judges could hear that announcement. It was announced over the Voice of America. Well, the question is, how did we know that it worked?