I. Origin, Heredity and Performance
In the previous articles statistics were given in regard to the birthplace of the scientific men, and data are now at hand in regard to the nationality and race of their parents. Of the thousand scientific men first selected 126 were born abroad—34 in Canada, 38 in Great Britain 
and 19 in Germany. Table I. gives the nationality of the parents of 917 leading scientific men. Six hundred and twenty-eight, or more than two thirds, have both parents of native American (United States) birth, 23 others have an American father and 42 an American mother, foreign men having American women more frequently than the reverse. In 165 cases both parents are foreign born and of the same nationality. Including Americans there are 124 marriages in which the nationality of the parents was mixed, but they were largely British. The American-born parents are mainly of British and New England descent; of foreign born parents, 137 fathers and an equal number of mothers are English, Scotch, Irish or Canadian. Germany contributes 77 fathers and 66 mothers. Other nations contribute in all 51 fathers and 44 mothers—fairly equally distributed among Norwegians, Swedes, Russians, Dutch, French and Swiss, with several from Denmark, Italy and Japan. The parents of American men of science are thus predominantly British-American, with an admixture of nearly 8 per cent, of Germans and about 5 per cent, from other nationalities.
Twelve and six tenths per cent, of our leading scientific men are foreign born, 12.6 per cent, are native born of foreign-born parents, and 7.1 per cent, have one foreign-born parent. In the general population of the United States 14 per cent, of the people are foreign born, 13.5 have both parents foreign born and 6.7 have one parent foreign born. The foreign born and those of foreign-born parentage thus contribute less, but only slightly less, than the native population to scientific productivity. There is a great difference in the different nationalities. Those born in Great Britain contribute 1.8 per cent to the population and 3.4 per cent, to our scientific men; Germany contributes 2.7 per cent, to the population and 1.9 per cent, to the scientific men; Russia 1.7 to the population and 0.6 to the scientific men; Italy 1.5 to
