United States. The tremendous bulk of this movement, together with the fact that it is drawn from such diverse and often mutually antagonistic races and nations, produces problems which not only are unique but whose proper solution is a matter of the gravest concern for the welfare and continuance of this country. The population of New York and of many sections elsewhere increases faster by immigration than by birth. These immigrants at best are only imperfectly and superficially sifted, and many enter to whom the privilege should be denied. The reason for this lies in the extreme difficulty of recognizing many physical and mental affections in their incipiency, in the shrewdness so often exhibited by the immigrant in concealing such defects, and in the loopholes that exist in the administration and interpretation of the law whereby many defectives who are detected are nevertheless admitted.
It goes without saying that the development of American ideas and standards in an immigrant foreign population will be inversely proportional to the density and homogeneity of that population in any section. Intermixture is the secret of assimilation. And assimilation is the test of desirable immigration. But not alone is the social and economic advance of the immigrant determined by his relations with Americans, for it is just, as true that the immigrant will affect the standards and ideals of the American. This influence of the immigrant on the native population becomes operative in many ways, but none of these is so important and yet so complicated as the influence on the physical, mental and social health of the general population.
