use 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.

Among the many passages in which Diderot touches on the differences
between poetry and painting, none is more just and true than that in
which he implores the poet not to attempt description of details: "True
taste fastens on one or two characteristics, and leaves the rest to
imagination. 'Tis when Armida advances with noble mien in the midst of
the ranks of the army of Godfrey, and when the generals begin to look at
one another with jealous eyes, that Armida is beautiful to us. It is
when Helen passes before the old men of Troy, and they all cry out--it
is then that Helen is beautiful. And it is when Ariosto describes Alcina
from the crown of her head to the soles of her feet, that
notwithstanding the grace, the facility, the soft elegance of his verse,
Alcina is not beautiful. He shows me everything; he leaves me nothing to
do; he makes me wearied and impatient. If a figure walks, describe to
me its carriage and its lightness; I will undertake the rest. If it is
stooping, speak to me only of arms and shoulders; I will take all else
on myself. If you do more, you confuse the kinds of work; you cease to
be a poet, and become a painter or sculptor. One single trait, a great
trait; leave the rest to my imagination. That is true taste, great
taste."[64] And then he quotes with admiration Ovid's line of the
goddess of the seas:

Nec brachia longo
Margine terrarum porrexerat Amphitrite.

[64] _Oeuv._, xi. 328.

Quel image! Quels bras! Quel prodigieux mouvement! Quelle figure! and so
forth, after Diderot's manner.

Nobody will compare these detached and fragmentary deliverances with the
full and easy mastery which Lessing, in _Laocoeon_ and its unfinished
supplements, exhibit