[61] It is to be observed also that he shows true perspicacity in connecting the difficulty of transforming a poetic into a pictorial description, with the kindred difficulty of translating a finished poem in one language into another language. See also xi. 107. Diderot's answer to the question is an anticipation of the main position of the famous little book which appeared fifteen years afterwards, and which has been well described as the Organum of aesthetic cultivation. In _Laocooen_ Lessing contends against Spence, the author of _Polymetis_ against Caylus, and others of his contemporaries, that poetry and painting are divided from one another in aim, in effects, in reach, by the limits set upon each by the nature of its own material.[62] So Diderot says that the painter could not seize the Virgilian moment, because a body that is partially immersed in water is disfigured by an effect of refraction, which a faithful painter would be bound to reproduce; because the image of the body could not be seen transparently through the stormy waters, and therefore the god would have the appearance of being decapitated; because it is indispensable, if you would avoid the impression of a surgical amputation, that some visible portion of hidden limbs should be there to inform us of the existence of the rest.[63] He takes another instance, where a description that is admirable in poetry would be insupportable in painting. Who, he asks, could bear upon canvas the sight of Polyphemus grinding between his teeth the bones of one of the companions of Ulysses? Who could see without horror a giant holding a man in his enormous mouth, with blood dripping over his head and breast? [62] Lessing appears to have been directly led to this by Aristotle. See Gotschlich's _Lessing's Aristotelische Studien_, p. 120. [63] _Oeuv._, i. 382, 403.