In taking up the special study of immigration, it is necessary to bear in mind at the outset that the word is to be used in a limited and semitechnical sense. It is not always so used in common speech nor even in scientific writings, and much confusion and inaccuracy not infrequently result. Let us state once more exactly what is meant by immigration. Immigration is a movement of people, individually or in families, acting on their own personal initiative and responsibility, without official support or compulsion, passing from one well-developed country (usually old and thickly settled) to another well-developed[11] country (usually new and sparsely populated) with the intention of residing there permanently. The same movement may equally well be referred to as emigration. It is obviously only a question of the point of view. The two words may be used interchangeably without danger of confusion, if the point of view is regarded. There is only one movement, and one set of people, emigrating from one country and immigrating to another.[12] As observed in the foregoing chapter, immigration is a movement which could not have originated before the Discoveries Period, and did not, in fact, become a matter of much importance until a century or so later. The countries which are now the objective points of large streams of immigration are, without exception, countries which have been opened up since that epoch. An exhaustive study of immigration should take up each of these countries in turn, and examine conditions in Canada, Argentina, South Africa, Australasia, and the United States. The plan of the present volume does not include so exhaustive a treatment; it is intended primarily for American readers. The specific study of immigration will be limited to the United States. This is the more justifiable, inasmuch as the United States is, beyond comparison, the foremost country in immigration movements, both in point of numbers and of world interest. All the fundamental principles of immigration are exemplified here more fully than in any other country. To the citizen of the United States it is a matter of the greatest importance and interest, for it has to do with a unique subject—the make-up of the American people itself.