Professor Franz Boas, in his study of “Changes in the Bodily Form of Descendants of Immigrants,” which forms a part of the report of the Immigration Commission, and has attracted wide attention, lays much stress on the change in environment which follows immigration. He reaches the conclusion that there is a tendency manifest in the American-born children of immigrants to approach a common physical type in this country, and that this tendency becomes more marked as the mother’s length of residence in the United States, previous to the birth of the child, increases. His main investigations are concerned with the head form, and have to do particularly with Sicilians and east European Hebrews. The cephalic index has always been considered one of the most permanent of race characters, but Professor Boas’s figures seem to show that the naturally long-headed Sicilians tend to become less so in this country, while the relative length of head of the naturally brachycephalic Hebrews increases. The results reached by Professor Boas are somewhat startling, and challenge attention. It is to be hoped that they will be subjected to the most careful scrutiny by anthropologists qualified either to verify or to correct them. Until they have been thus tested they can be accepted only tentatively. On the face of them they suggest certain weaknesses or limitations. In the first place, they are concerned with too few races, and too few individuals in each race, to justify general conclusions. Again, they are concerned almost wholly with persons under twenty years of age, who are naturally still in a plastic state. It would be much more significant if it could be shown that this tendency still persisted after the individuals were fully matured. Furthermore, the curves show a decided tendency to lose their regularity, and go to pieces, in the upper ages tabulated, either because there were too few individuals in those age groups to afford regularity, or because the tendencies actually diminish as age advances. Finally, it must be said that if the mere change of residence from eastern Europe or southern Italy to America is sufficient to produce a complete change of head form in the offspring, it can only mean that after all the head form is not such a permanent race character as has been supposed, and really has little significance. Certainly we should avoid such sweeping deductions from this study as Professors Jenks and Lauck make in the statement, “If these physical changes are so great, we may well conclude that the whole mental and even the moral constitution of the people may also rapidly change under the new conditions.”[361]