Hair?
"They're like Napoleon's army in Moscow. They have occupied a lot of territory, and they think they've won the war. And yet they are very exposed in a hostile climate with a population that's very much unfriendly."
"That's the case with the Darwinists in the United States. The majority of the people are skeptical of the theory. And if the theory starts to waver a bit, it could all collapse, as Napoleon's army did in a rout."