Note 2 — EVERYDAY ACTUALITIES.—NO. XX.
Reading edition
"The colorless, fresh-cut surfaces of a potato, of a turnip, or of an apple, when exposed to the air, soon become brown. In all such substances, the presence of a certain quantity of water, by which the molecules are enabled to move freely on one another, is a condition necessary to the production, by temporary contact with air, of a change in form and composition, a resolving of the original body into new products, which continues uninterrupted till no part of the original compound is left. This process has been distinguished by the name of putrefaction."—Liebig.