External design in Gothic buildings depends almost entirely upon contrast for its power of charming the eye, and it is this circumstance which has left the successive generations of men who toiled at our great Gothic cathedrals so free to follow the bent of their own taste in their additions, rather than that of their forerunners.
But setting aside the irregularities due to the caprice of various builders, and the constant changes which took place in detail through the Gothic period, it is to contrast that we must trace most of the surprising effects attained by the architecture of the Middle Ages. The rich tracery was made richer by contrast with plain walls, the loftiest towers appeared higher from their contrast with the long level lines of roofs and parapets.
It is, in truth, one of the principal marks of the decadence which began in the fifteenth century that the principle of contrast was, to a considerable extent, abandoned, at least in the details of the buildings if not in their great masses. Walls were at that time panelled in imitation of the tracery of the adjoining windows, and no longer acted as a foil to them by their solid plainness; long rows of pinnacles, all exactly alike, followed the line of the parapets, and a repetition of absolutely identical features became the rule for the first time in the history of Gothic art.
There can be no doubt that had this modification run its natural course unchecked and undisturbed by the change in taste which abruptly brought the Gothic period to a close, it must have resulted in the deterioration of the art.
