so far as roundness of head is concerned. If American environment can bring about a modification of head form in the first generation, the question presents itself, may it not be that other characteristics may be as easily modified? A comparison of the width of face of Bohemians with facial width of American-born individuals was made. When the Bohemians were arranged according to their ages at the time of immigration, the results showed that there was a loss among those who had come here as young children. When this comparison was continued with the Americans, born one, two, and more years after the arrival of their mothers, the width of face was seen to decrease still further. It appears that American environment caused a retardation of the growth of the width of face. Professor Boas concludes, "I think, therefore, that we are justified in the conclusion that the removal of the east European Hebrew to America is accompanied by a marked change in type, which does not affect the young child born abroad and growing up in American environment, but which makes itself felt among the children born in America, even a short time after the arrival of the parents in this country. The change of type seems to be very rapid, but the changes continue to increase so that the descendants of immigrants born a long time after the arrival of the parents in this country differ more from their parents than do those born a short time after the arrival of the parents in the United States." 13 If this process of change explains the difference between racial types in America it is possible that the same environmental influence has operated in the past to produce many of the racial types which appear stable to-day. In considering these conclu13 Changes in the Bodily Form of Descendants of Immigrants, p. 52.

sions we must remember that the evidence which we have points to the fact that neither environment nor training can produce, in the sense of originating, human characteristics, good or bad. But it is environment that determines whether given characteristics, when born into the world, shall perish by starvation or conflict, or shall survive and perpetuate themselves in following generations. Perhaps the most obvious and rigorous effect of phys. ical environment is the selective influence exercised by climatic gradations from extreme heat to extreme cold, and from excessive aridity to excessive moisture. Physical environment sets limits to human habitation. Life is maintained with great difficulty in the Arctic and Antarctic regions.14 In the Torrid regions activities must be confined to the comparative cool of the early morning or the evening. The intense heat of mid-day makes inaction necessary.

The heat belt, that section of the globe lying roughly between 30° north latitude and 30° south latitude where the mean annual temperature is 68° Fahrenheit, is inhabited by peoples who have during the last five hundred years contributed little to human advancement. The natives of the tropics and sub-tropics, of Mexico, the Central American republics, the West Indies, the greater part of South America, practically the whole of Africa, Arabia, India, Burma, Indo-China, the Malay Peninsula, the Malay Archipelago, Polynesia, and the Philippine Islands, have contributed an almost negligible addition to art, literature, science and thought. It has been the inhabitants of those countries which lie outside the heat belt, the Continent of Europe, the United Kingdom, the United States, Canada, Australia, Central and Northern 14 See figures 49 and 50.

Asia, Japan, and the greater part of China, that have achieved things in art, literature and science during the last one thousand years.15 Climate affects the energy and regularity with which labor is conducted. Extreme heat such as exists in the torrid and semi-torrid regions mentioned, tends to enervate the worker, whether he be manual laborer or brain worker. Prolonged and persistent labor is impossible. The result is unstable and irresponsible methods of life. Regular habits are not easy to cultivate when heat makes effort desultory.16

17

Climatic conditions in the far north are such as to interfere with the regularity of labor. The intense cold benumbs the limbs and interferes with freedom of movement. It depresses the normal operation of the vital processes and dulls ambition. "Thus we find that no people living in a very northern latitude have ever possessed that steady and unflinching industry for which the inhabitants of temperate regions are remarkable. The reason for this becomes clear when we remember that in the more northern countries the severity of the weather and, at some seasons, the deficiency of light render it impossible for people to continue their usual out-of-door employments." 18 In cold climates the bodily warmth necessary to sustain vital processes in a normal state is maintained by the consumption of large quantities of oily food, such as whale oil, and blubber. But this highly carbonized food, although very essential, is quite scarce. It can be obtained only from the fat and oils of powerful and ferocious animals. This lack of sufficient food affects the numbers of the people. Deficiency of

15 Ireland, A.-The Far Eastern Tropics, pp. 2-4.

16 Buckle, H. T.-History of Civilization in England, 1857-1861, ch. ii. 17 See figure 51.

18 Ibid.