Read it through once

"For more than twenty years I have amused my compulsory leisure with collecting these curious physical signatures in this town. At my house I have hundreds upon hundreds of them. Each and every one is labelled with name and date; not labelled the next day or even the next hour, but in the very minute that the impression was taken. When I go upon the witness stand I will repeat under oath the things which I am now saying. I have the finger-prints of the court, the sheriff, and every member of the jury. There is hardly a person in this room, white or black, whose natal signature I cannot produce, and not one of them can so disguise himself that I cannot pick him out from a multitude of his fellow-creatures and unerringly identify him by his hands. And if he and I should live to be a hundred I could still do it. [The interest of the audience was steadily deepening, now.]