About a year ago, a grad student came running up to Wolfgang Kuebler, looking all excited: The mice, he said — well, to be honest, the mice didn’t look great, but they looked a heck of a lot better than they did before.
Not long before, Kuebler’s students at The Charité in Berlin had anesthetized mice and dropped a bit of Streptococcus pneumoniae down their throats, just enough to sicken but not kill. The mice quickly lost weight, temperature, and appetite. They looked “runty,” said Kuebler.