Authors:

How Instinct varies in the grov'ling swine.

Alexander Pope, William Roscoe (1847). “The works of Alexander Pope, esq., with notes and illustrations, by himself and others. To which are added, a new life of the author, an Estimate of his poetical character and writings, and occasional remarks by William Roscoe, esq”, p.46
How Instinct varies in the grov'ling swine.