The fingers of one hand shift, a rare unclear gesture. There are complications still, no doubt, and Tam's notes speak of a few and hint at others, but --

"Boiling water before consuming it. Cooking vegetables. Washing hands frequently with soap, boiling surgical instruments or washing them in strong spirits."

This is not a clear explanation. He should be mentioning the underlying causes first. To Combeferre, he would; to Combeferre, he would simply hand over Tam's papers, tell them to speak, without this need for a double layer of intermediaries.

"At a conservative estimate: a ninety percent reduction of the risk of contagion of cholera."

Courfeyrac was there for those months of epidemic and horror. And all the other illnesses that kill the old, the young, the poor, the merely unlucky -- a lifetime of knowing that as a background, and then the years of seeing their friends' sorrow and rage for everything they didn't know and couldn't heal.

A death away, at home, with everything and everyone they loved, except their few fellow ghosts.