The language of prose is often imaginative to a high degree, but seldom if ever to that extent or with that deliberate purpose which in verse is nothing less than essential. Genuine poetry differs from prose in the entire texture of its web. From the same threads the loom may weave plain stuff or richest brocade; and thus of much the same words are made prose and poetry. The difference lies chiefly in the fashion of working.

The essentials of the manner of poetry being language metrical and imaginative, the essential of the matter is that it be the expression of passionate emotion. By passionate emotion is meant any feeling, powerful or delicate, which is capable of filling the whole soul; of taking possession for the time being of the entire man. It may be fierce hate, enthralling love, ambition, lust, rage, jealousy, joy, sorrow, any over-mastering mood, or it may be one of those intangible inclinations, those moods of mist, ethereal as hazes in October, those caprices of pleasure or sadness which Tennyson had the art so marvelously to reproduce. Passionate emotion is by no means necessarily intense, but it is engrossing. For the time being, at least, it seems to absorb the whole inner consciousness.

It is the completeness with which such a mood takes possession of the mind, so that for the moment it is to all intents and purposes the man himself, that gives it so great an importance in human life and makes it the fitting and the sole essential theme of the highest art. Behind all serious human effort lies the instinctive sense of the fitness of things. The artist must always convince that his end is worthy of the means which he employs to reach it; and it follows naturally that the writer who uses imaginative diction and the elaborateness of metre must justify this by what he embodies in them. Metrical forms are as much out of place in treating of the material concerns of life as would be court robes or religious rites in the reaping of a field or the selling of a cargo of wool. The poet is justified in his use of all the resources of form and of poetic diction by the fact that the message which he is endeavoring to convey is high and noble; that the meaning which he attempts to impart is so profoundly subtle as to be inexpressible unless the words which he employs are assisted by the language of rhythm and metre.

That the reader unconsciously recognizes the fact that the essential difference in the office of prose and poetry makes inevitable a difference also of method, is shown by his dissatisfaction when the writer of prose invades the province of poetry. The arrangement of the words of prose into systematic rhythm produces at once an effect of weakness and of insincerity. Dickens in some of his attempts to reach deep pathos has made his prose metrical with results most disastrous. The mood of poetry is so elevated that metrical conventions seem appropriate and natural; whereas in the mood of even the most emotional prose they appear fantastical and affected. The difference is not unlike that between the speaking and the singing voice. A man who sang in conversation, or even in a highly excited oration, would simply make himself ridiculous. In song this manner of using the voice is not only natural but inevitable and delightful. What would be uncalled for in the most exalted moods of the prose writer is natural and fitting in the case of the poet, because the poet is endeavoring to embody, in language the most deep, the most high, the most delicate experiences of which humanity is capable. The form is with him a part of his normal language. To say in prose: "My love is like a red rose newly sprung in June, or like a melody beautifully played," means not much. Yet the words themselves are not widely varied from those in which Burns conveys the same ideas with so great an added beauty, and so much more emotional force:—

Oh, my luve's like a red, red rose
That's newly sprung in June;
Oh, my luve's like a melodie
That's sweetly played in tune.

The metrical cadences woo the ear like those of a melody sweetly played, and to that which the words may say or suggest they add an effect yet more potent and delightful.

A moment's consideration of these facts enables one to estimate rightly the stricture made by Plato:—

You have often seen what a poor appearance the tales of poets make when stripped of the colors which music puts upon them, and recited in prose. They are like faces which were never really beautiful, but only blooming, and now the bloom of youth has passed away from them.

It would be more just and more exact to say that they are like the framework of a palace from which have been stripped the slabs of precious marble which covered it. It is neither more nor less reasonable to object to poetry that its theme told in prose is slight or dull than it would be to scorn St. Peter's because its rafters and ridgepole might not be attractive if they stood out bare against the sky. The form is in poetry as much an integral part as walls and roof and dome, statues and jewel-like marbles, are part of the temple.

Leaving out of consideration those peculiarities such as rhyme and special diction, which although often of much effect are not essential since poetry may be great without them, it is sufficiently exact for a general examination to say that the effects of poetry are produced by the threefold union of ideas, suggestion, and melody. In the use of ideas poetry is on much the same footing as prose, except in so far as it deals with exalted moods which have no connection with thoughts which are mean or commonplace. In the use of suggestion poetry but carries farther the means employed in imaginative prose. Melody may be said practically to be its own prerogative. The smoothest flow of rhythmical prose falls far below the melodious cadences of metrical language; and in this manner of appeal to the senses and the soul of man verse has no rival save music itself.