a powerful monitor in the brain of the pig teaches him to seek for
relief and medicine. To open the pores of his skin, blocked up with mud,
and excite perspiration, he resorts to a tree, a stump, or his
trough--anything rough and angular, and using it as a curry-comb to his
body, obtains the luxury of a scratch and the benefit of cuticular
evaporation; he next proceeds with his long supple snout to grub up
antiscorbutic roots, cooling salads of mallow and dandelion, and,
greatest treat of all, he stumbles on a piece of chalk or a mouthful of
delicious cinder, which, he knows by instinct, is the most sovereign
remedy in the world for that hot, unpleasant sensation he has had all
the morning at his stomach.