Eye vs. ear

From Henry James' preface to the New York Edition revision of The Golden Bowl:

It is scarce necessary to note that the highest test of any literary form conceived in the light of 'poetry' - to apply that term in its largest literary sense - hangs back unpardonably from its office when it fails to lend itself to viva-voce treatment. We talk here, naturally, not of non-poetic forms, but of those whose highest bid is addressed to the imagination, to the spiritual and the aesthetic vision, the mind led captive by a charm and a spell, an incalculable art. The essential property of such a form as that is to give out its finest and most numerous secrets, and to give them out most gratefully, under the closest pressure - which is of course the pressure of the attention articulately sounded.