^*The critics made some valid points. Clearly the attacking organism does not entirely determine whether someone gets sick. The same organism can attack two people, kill one, and not cause any symptoms in the other. An individual’s genes, immune system, environment, and even such factors as stress all affect susceptibility.
      As late as 1911 the head of the school training French army doctors in public health said that germs alone were “powerless to create an epidemic.” But that particular view was by then an idiosyncratic, not simply minority, opinion.