Assimilation is a spiritual metamorphosis. It manifests itself in many changes of dress, of language, of manners, and of conduct. But these outward semblances are not assimilation. An alien is thoroughly assimilated into a new society only when he becomes completely imbued with its spiritual heritage. He must cease to think and feel and imagine in ways determined by his old social environment, and must respond to the stimuli of social contact in all ways exactly as if from the very beginning he had developed under the influence of his adopted society. And this involves, of course, the entire abandonment of any sympathy, affection, or loyalty different from that which might be felt by any native of his new home for the country of his origin or the people of that country. Complete assimilation so defined may seem impossible to the adult immigrant. This is almost universally the truth. The spiritual impress of the environment of one's infancy, childhood, and youth, can seldom be eradicated during the later years of life. Realizing this, those who hate to admit that our immigrants are not being assimilated, hasten to modify the definition. But this does not help the case, because it does not alter the situation.
In this respect, the war has already rendered a distinct service to this country. No longer can we blind ourselves to the fact that national unity does not exist. Professor William Graham Sumner used often to remark that the United States had no just claim to the name of nation, because of the presence of the negroes within its borders. Whether that particular definition of "nation" is adopted or not, there can be no doubt that real national homogeneity is wholly lacking, and that the negro is by no means the only discordant element. In fact, in many ways the immigration problem is more imminent and menacing than the negro problem: for the negro problem is in a sense static, since it is not aggravated by continuous accessions from without. We know what the negro problem is, and can state it in terms which will be relatively permanent. But the immigration problem presents constantly changing aspects, not only because of its growing numerical proportions, but because of the diversity of its elements, and the uncertainty as to its future developments.