The Romans made a step further towards a more direct imitation of nature in their employment of the acanthus leaf. As applied to a capital, or where the constructive form of the bell beneath it is still distinctly seen, it is not only unobjectionable, but productive of the most pleasing effect. Indeed it is doubtful if anything of its class has yet been invented so entirely satisfactory as the Roman Corinthian order, as found, for instance, in the so-called Temple of Jupiter Stator at Rome. The proportions of the order have never yet been excelled, and there is just that balance between imitation of nature and conventionality which is indispensable. It is not so pure or perfect as a Grecian order, but as an example of rich decoration applied to an architectural order it is unsurpassed. With their disregard of precedent and untrammelled wildness of imagination, the Gothic architects tried every form of vegetable ornament, from the purest conventionalism, where the vegetable form can hardly be recognised, to the most literal imitation of nature. While confining himself to purely lithic forms, an architect can never sin against good taste, though he may miss many beauties; with the latter class of ornament he is always in danger of offence, and few have ever employed it without falling into mistakes. In the first place, because it is impossible to imitate perfectly foliage and flowers in stone; and secondly, because if the pliant forms of plants are made to support, or do the work of, hard stone, the incongruity is immediately apparent, and the more perfect the imitation the greater the mistake. [Illustration: No. 5.] [Illustration: No. 6.] In the instance (Woodcut No. 5), any amount of literal imitation that the sculptor thought proper may be indulged in, because in it the stone construction is so apparent everywhere, that the vegetable form is the merest supplement conceivable; or in a hollow moulding round a doorway, a vine may be sculptured with any degree of imitation that can be employed; for as it has no more work to do than the object represented would have in the same situation, it is a mere adjunct, a statue of a plant placed in a niche, as we might use the statue of a man: but if in the woodcut (No. 6) imitations of real leaves were used to support the upper moulding, the effect would not be so satisfactory; indeed it is questionable if in both these last examples a little more conventionality would not be desirable.