Summing up the facts regarding the volume and racial character of immigration during this period, it appears that, as regards the former, the series of waves has been continued, responding to the economic conditions, but reaching a much higher culmination than ever before. As regards the latter, there has been a most distinct and profound change. The main source of the immigrant current has shifted away from northern and western Europe, to the southern and eastern portions of the continent, whose people are by no means so closely related in physique or so similar in mental characteristics to the people of the United States as the immigrants of earlier periods. The causes of this change lie primarily in altered conditions in the United States which make it less attractive to the residents of the more advanced nations of Europe than formerly. In the more backward countries the political and economic situation is still so inferior to the United States that an ample motive for emigration exists. All that was needed to start a large movement was a knowledge of the possibilities across the Atlantic, and the means of getting there. Both of these have been provided within the period in question. CHAPTER VIII THE CAUSES OF IMMIGRATION There are two things which the student of sociological problems—like every other scientist—wishes to know about the phenomena which fall within his field. These are the causes and the effects. Hitherto we have said a good deal about the causes of immigration and very little about the effects. In truth, it is much simpler to predicate causes of such a movement than effects. The causes lie in the past; the effects are largely a matter of the future. It is possible to state with a fair degree of certainty what are the causes of the modern immigration to the United States. The reader will have already formed a general idea from the examples of the new immigration which we have given.