when seen from the front, and long when seen in profile), this number will be low; when it is rounded (that is, wide when seen from the front, and short when seen in profile), this number will be high. The width of the head expressed in per cents of the length of the head is about 78 per cent among Sicilians born in Sicily and about 83 per cent among Hebrews born in eastern Europe. Among Sicilians born in America this number rises to more than 80 per cent, while among east European Hebrews born in America it sinks to 81 per

cent.

This fact is one of the most suggestive discovered in the investigation, because it shows that not even those characteristics of a race which have proved to be most permanent in their old home remain the same under the new surroundings; and we are compelled to conclude that when these features of the body change, the whole bodily and mental make-up of the immigrants may change.

These results are so definite that, while heretofore we had the right to assume that human types are stable, all the evidence is now in favor of a great plasticity of human types, and permanence of types in new surroundings appears rather as the exception than as the rule. The disagreement of the changes in distinct types may be illustrated by Table 1 and figure 1 following, which show the head form of Sicilians and east European Hebrews of American birth in comparison with that of Sicilians and east European Hebrews of European birth.

TABLE 1.-Cephalic index, or width of head expressed in per cent of length of head, of foreign-born and American-born Hebrews and Sicilians.

The diagram shows very clearly that the two races are quite distinct in Europe and that their descendants born in America differ from their parents in opposite directions.

FIG. 1.-Comparison of head form of American-born and foreign-born Hebrew and Sicilian males. Scale, 1 square=0.5 unit.

The measurements of males of 5 years of age and older are indicated in this diagram. The head form, expressed by the ratio between width and length of head, and its change with increasing age, is indicated by the four lines. The diagram shows that foreign-born Sicilian males have the lowest value for this ratio and the foreign-born Hebrews the highest, while the American-born Hebrews and the American-born Sicilians stand between these two extremes, and are more alike than foreignborn individuals of the same races.

In order to understand the causes which bring about these alterations of type, it is necessary to know how long a time must have elapsed since the immigration of the parents to bring about a noticeable change of type of the offspring. This investigation has been carried out mainly for the cephalic index, which during the period of growth of the individual undergoes only slight modifications. It appears in those cases that contain many individuals whose parents have been residents of America for a long time that the influence of American environment upon the descendants of immigrants increases with the time that the immigrants have lived in this country before the birth of their children.

We have proved this statement by comparing the features of individuals of a certain race born abroad, born in America within. ten years after the arrival of the mother, and born ten years or more after the arrival of the mother. It appears that the longer the parents have been here, the greater is the divergence of the descendants from the European type. The development may be illustrated by a comparison of Hebrews and Sicilians. The approach of the Hebrew and Sicilian types becomes very clear when we divide the Americanborn descendants into those born less than ten years after the arrival of the mothers and those born ten years or more after the arrival of the mothers. Since adult American-born Italians are few in number, it seemed best to compare individuals of an average age of about 9 years. Table 2 and figure 2, next presented, show the results of this comparison.

TABLE 2-Cephalic index of Hebrew and Sicilian boys; foreign-born, those born in America within ten years after arrival of mother, and those born ten years or more after arrival of mother.

FIG. 2.-Comparison of head form of Hebrews and Sicilians, arranged according to time elapsed between birth and immigration.

At 1 is indicated the head form expressed by the ratio between width and length of head of foreignborn Hebrews and Sicilians; at 2, the same ratios for those born within ten years after the arrival of their mothers in the United States; at 3, the corresponding values for those born more than ten years after the arrival of their mothers in America. The diagram shows the very rapid approach of the two types among children born shortly after the arrival of their mothers in America, and the slower continuation of this approach among children born a long time after the arrival of their mothers in America.

In figure 3 the form of the head of Sicilians and Hebrews is shown as seen from above. In the upper row the more rounded form of the foreign-born Hebrew is placed side by side with the more elongated form of the Sicilian. Below these is shown the head form of the descendants of the Hebrews and Sicilians born more than ten years after the arrival of the mothers. This figure is intended only

to give an impression of the change in proportions. It does not represent the head forms in other directions in detail.

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Showing (1) the average form of the head of the foreign-born Hebrew; (2) the average form of the head of the foreign-born Sicilian; (3) the average form of the head of the American-born Hebrew and Sicilian born more than ten years after the arrival of the mother in America. These sketches are intended only to give an impression of the change in proportions. They do not represent the head forms in detail.

MEASUREMENTS OF DISTINCT TYPES.

In the following pages a condensed tabulation and graphical representation of the measurements of various types are given.

TABLE 3.-Measurements of foreign-born and American-born Bohemians, Slovaks, Hungarians, and Poles, combined.

6 years..

67 120.9

13 119.5

13.3

15.2