Chapter XCV: Section LVII: But there is one character of Byzantine work which,

according to the time at which it was employed, may be considered as either fitting or unfitting it for distinctly ecclesiastical purposes; I mean the essentially pictorial character of its decoration. We have already seen what large surfaces it leaves void of bold architectural features, to be rendered interesting merely by surface ornament or sculpture. In this respect Byzantine work differs essentially from pure Gothic styles, which are capable of filling every vacant space by features purely architectural, and may be rendered, if we please, altogether independent of pictorial aid. A Gothic church may be rendered impressive by mere successions of arches, accumulations of niches, and entanglements of tracery. But a Byzantine church requires expression and interesting decoration over vast plane surfaces,--decoration which becomes noble only by becoming pictorial; that is to say, by representing natural objects,--men, animals, or flowers. And, therefore, the question whether the Byzantine style be fit for church service in modern days, becomes involved in the inquiry, what effect upon religion has been or may yet be produced by pictorial art, and especially by the art of the mosaicist?