(4) _The Racial or Biological Argument._ Undoubtedly the strongest arguments in favor of further restriction upon immigration into the United States are of a biological nature. The peoples that are coming to us at present belong to a different race from ours. They belong to the Slavic and Mediterranean subraces of the white race. Now, the Slavic and Mediterranean races have never shown the capacity for self-government and free institutions which the peoples of Northern and Western Europe have shown. It is doubtful if they have the same capacity for self-government. Moreover, the whole history of the social life and social ideals of these people shows them to have been in their past development very different from ourselves. Of course, if heredity counts for nothing it will only be a few generations before the descendants of these people will be as good Americans as any. But this is the question, Does heredity count for nothing? or does blood tell? Are habits of acting and, therefore, social and institutional life, dependent, more or less, on the biological heredity of peoples, or are they entirely independent of such biological influence? There is much diversity of opinion upon this question, but perhaps the most trustworthy opinion inclines to the view that racial heredity, even between subraces of the white race, is a factor of great moment and must be taken into account. It is scarcely probable that a people of so different racial heredity from ourselves as the Southern Italians, for example, will develop our institutions and social life exactly as those of the same blood as ourselves. It is impossible to think that the Latin temperament would express itself socially in the same ways as the Teutonic temperament. Certainly the coming to us of the vast numbers of peoples from Southern and Eastern Europe is destined to change our physical type, and it seems also probable that if permitted to go on it will change our mental and social type also. Whether this is desirable or not must be left for each individual to decide for himself.