Which rhetorical device is used in this excerpt from "The Extraordinary American" by G. K. Chesterton?

He was a lean brown man, having rather the look of a shabby tropical traveller, with a grey moustache and a lively and alert eye. But the most singular thing about him was that the front of his coat was covered with a multitude of shining metallic emblems made in the shape of stars and crescents. I was well accustomed by this time to Americans adorning the lapels of their coats with little symbols of various societies; it is a part of the American passion for the ritual of comradeship. There is nothing that an American likes so much as to have a secret society and to make no secret of it. But in this case, if I may put it so, the rash of symbolism seemed to have broken out all over the man, in a fashion that indicated that the fever was far advanced.