The hog is a domestic animal descended from the wild boar of Europe and Asia. The flesh of the hog is used universally as food, its hide is made into a good quality of leather, and the bristles are used to make brushes. The flesh, because of the quantities of salt it can absorb, is more extensively cured than is the flesh of any other animal. The Jewish and Muslim religions forbid the use of pork, stigmatizing the hog as an unclean animal. Yet the hog's fondness for mud baths is easily accounted for; the animal is a pachyderm, that is, it has a more than ordinarily thick skin, as have the hippopotamus and rhinoceros, and wet, cool mud plastered onto its hide furnishes about the only source of coolness of a constancy to insure penetration of the skin. Yet the filthy hog wallow is not essential to the animal's health; it thrives in clean sanitary surroundings as well as any other domestic animal, as hog raisers now know.
    Hogs are more extensively bred in Europe and North America (especially the United States) than on the, other continents. Some excellent breeds have been developed, so that one type produces an excess of lard while another will produce more bacon. The breeds that are best known are Yorkshire, Poland-China, Chester, Tamworth, Berkshire, Hampshire, Essex and Duroc. The great Mississippi Valley of the United States is the most important hog-raising area in the world; and lowa is the principal hog-raising state in the United States.