The Book of Household Management by Mrs. Beeton

773. TO COUNTERACT THE CONSEQUENCE OF A VIOLATION OF THE PHYSICAL LAWS,

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.