He can tell at a glance who's got Bright's Disease in their kidneys and who ain't.

His own father, he says, was deathly sick fur years and years and never knowed it, and the knowledge come on him sudden like, and he died.
That was before Siwash Injun Sagraw was ever found out about.

Doctor Kirby broke down and cried right there in the wagon when he thought of how his father might of been saved if he was only alive now that that medicine was put up into bottle form, six fur a five-dollar bill so long as he was in town, and after that two dollars fur each bottle at the drug store.
He unrolled a big chart and the Injun helt it by that there gasoline lamp, so all could see, turning the pages now and then.

It was a map of a man's inside organs and digestive ornaments and things.

They was red and blue, like each organ's own disease had turned it, and some of 'em was yaller.