Acclimatization, a change in a plant or an animal enabling it to live in a new locality in a climate for which it was not at first fitted. Indian corn furnishes an excellent illustration. Seed corn from Mexico, for instance, planted in Minnesota would not ripen in time to escape fall frosts; but by choosing early ears of Mexican corn, and planting a little farther north from year to year, and repeating the process, an early corn may be developed which will ripen on the Canadian line. That is to say, corn which changes so that it ripens earlier, becomes acclimated. If northern seed be planted southward, the reverse process takes place. The successive generations or crops descended from early corn seemingly acquire the habit of taking more time, and thus become late corn again. A similar change may be observed in certain kinds of willows that grow to be trees in temperate climes, but grade off into copse wood and finally appear in arctic latitudes as low shrubs a hand's breadth in height. The seed of the tree would not produce a successful plant beyond the Arctic Circle; but, by traveling north slowly, the descendants of the tree become shrubs and adapt themselves to a short, warm summer, a cool soil, terrific winds, and a long, extremely cold, icebound winter. These willows are acclimated. Under arctic conditions the willows are dwarfed in size and rough in exterior, but they thrive, and are as thoroughly at home as the arctic fox and the ptarmigan to which they afford shelter. In the case of animals the process of adaptation is much the same. The thin-blooded, scanty-haired muskrat of the Louisiana bayous would have a hard time in the border swamps of Hudson Bay. Very likely at first it might fail to rear young, or might perish in the deeply frozen shallows; but with time a colony of these southern muskrats would learn to eat northern roots, to choose waters of suitable depth, and to build tepees. Their blood would thicken, their coats of fur would grow denser and longer. They and their descendants would become accustomed to new conditions and be prepared for them. They would be acclimated. People suffer great distress from extreme changes of climate. The people of England who go to India to occupy government positions, or to engage in commercial undertakings, suffer far more during the first years, and are more subject to pestilence, than is the case after a term of residence has enabled them to become acclimated. Americans are passing through the same experience in the Philippines. The less abrupt the change of climate, the greater the probability of acclimatization. An inhabitant of Mississippi is more likely to get on in the climate of Manila than is a man from Wisconsin. Residence on the Gulf Coast is a good preparation for residence at Panama. Contrariwise a Maine man or a Christiania sailor is a better hand for arctic exploration than a sailor enlisted at Genoa or Marseilles. For reasons of this sort, migrations of people, plants, and animals follow parallels of latitude more freely than lines running in a north and south direction. Farmers have understood this fact in a general way. Seed grains, fruit trees, cotton, horses, sheep, goats, and swine are not shifted north or south rapidly. A northern farmer desires northern grown seeds and patronizes a northern nursery when he desires to plant an orchard or a fruit garden; but by allowing time for acclimatization, the range through which useful plants may be cultivated, as, for instance, the corn and the apple, has been extended wonderfully. The term should be distinguished carefully from naturalization. The spread of rats, mice, rabbits, English sparrows, and weeds from Europe and other countries, without particular change of habits or form, is mere colonization or naturalization, not to be confounded with acclimatization. A naturalized plant or animal is not only acclimated, but is so much at home in the new region that it is able to get on and thrive without the help of man. It is to all appearances native. See AGRICULTURE; GRAPES; APPLE; CORN; SEED.