It is also clear that the forces of economic attraction in the United States do not play an altogether passive part in the Jewish immigration. The very fact of an immigrant-nucleus formed in this country and serving as a center of attraction to relatives and friends abroad--a force which increases in direct and multiple proportion to the growth of immigration--is an active and positive force in strengthening the immigration current. This was early understood by the _Alliance Israelite Universelle_ which had acted upon this principle in the seventies and had prophetically sought to direct a healthy movement of Jewish immigrants to this country in the hope of thereby laying a foundation for future Jewish immigration to this country. This current, however, once started and growing only by the force of its increasing attraction, would reflect in its movement almost wholly the economic conditions in this country. That so large a part of the Jewish immigration, and so many of the phenomena peculiar to it, find their explanation, for the largest part of the thirty years, in the situation and the course of events in the countries of Eastern Europe leads to the inevitable conclusion that the key to the Jewish immigration is to be found not in the force of economic attraction exercised in the United States but rather in the exceptional economic, social and legal conditions in Eastern Europe which have been created as a result of governmental persecution. Reviewing the various phases of the history of Jewish immigration for these thirty years, we are enabled to see more closely its nature. The study of the immigration, its movement and its social and economic characteristics, in comparison with those of other immigrant peoples, has revealed in it a number of distinguishing traits. In the causes of the emigration of the Jews, in the pressure exerted upon their movement as reflected in their rate of immigration, in their family movement, in the permanence of their settlement, and in their occupational distribution have been found characteristics which mark them off from the rest of the immigrant peoples. The number of these characteristics and the degree in which they are found in the Jewish immigration, put it in a class by itself.