§ XXXII. Observe, however, and this is of the utmost possible importance, that the value of this type does not consist in the mere shutting of the ornament into a certain space, but in the acknowledgment _by_ the ornament of the fitness of the limitation--of its own perfect willingness to submit to it; nay, of a predisposition in itself to fall into the ordained form, without any direct expression of the command to do so; an anticipation of the authority, and an instant and willing submission to it, in every fibre and spray: not merely _willing_, but _happy_ submission, as being pleased rather than vexed to have so beautiful a law suggested to it, and one which to follow is so justly in accordance with its own nature. You must not cut out a branch of hawthorn as it grows, and rule a triangle round it, and suppose that it is then submitted to law. Not a bit of it. It is only put in a cage, and will look as if it must get out, for its life, or wither in the confinement. But the spirit of triangle must be put into the hawthorn. It must suck in isoscelesism with its sap. Thorn and blossom, leaf and spray, must grow with an awful sense of triangular necessity upon them, for the guidance of which they are to be thankful, and to grow all the stronger and more gloriously. And though there may be a transgression here and there, and an adaptation to some other need, or a reaching forth to some other end greater even than the triangle, yet this liberty is to be always accepted under a solemn sense of special permission; and when the full form is reached and the entire submission expressed, and every blossom has a thrilling sense of its responsibility down into its tiniest stamen, you may take your terminal line away if you will. No need for it any more. The commandment is written on the heart of the thing. § XXXIII. Then, besides this obedience to external law, there is the obedience to internal headship, which constitutes the unity of ornament, of which I think enough has been said for my present purpose in the chapter on Unity in the second vol. of "Modern Painters." But I hardly know whether to arrange as an expression of a divine law, or a representation of a physical fact, the alternation of shade with light which, in equal succession, forms one of the chief elements of _continuous_ ornament, and in some peculiar ones, such as dentils and billet mouldings, is the source of their only charm. The opposition of good and evil, the antagonism of the entire human system (so ably worked out by Lord Lindsay), the alternation of labor with rest, the mingling of life with death, or the actual physical fact of the division of light from darkness, and of the falling and rising of night and day, are all typified or represented by these chains of shade and light of which the eye never wearies, though their true meaning may never occur to the thoughts.