The power which causes the several portions of the plant to help each other, we call life. Much more is this so in an animal. We may take away the branch of a tree without much harm to it; but not the animal's limb. Thus, intensity of life is also intensity of helpfulness — completeness of depending of each part on all the rest. The ceasing of this help is what we call corruption; and in proportion to the perfectness of the help, is the dreadfulness of the loss. The more intense the life has been, the more terrible is its corruption.

Volume V, part VIII, chapter 1, section 4 (1860). - Modern Painters (1843-1860)