It is even more difficult to postulate the causes of crime than of pauperism. Until the criminologists have furnished us with a more efficient means of determining the causes of crime in general, there can be no profit in the attempt to classify the causes of crime among a particular group of the population. In respect to the nature of crime committed by different races, there seems to be something in the racial character of some of our immigrants which predisposes them in a certain direction, as exemplified in the preceding paragraph. There is also evidence that among some of the newer immigrants, crime is largely a matter of economic position. This is well illustrated by the case of the Greeks. Among the members of this very recent immigrant group, there has been a noteworthy decline in the average of criminality within the last few years, and the explanation appears to be that the crimes of the Greeks are such as correspond with a low economic situation—violations of corporation ordinances, of the sanitary code, etc. As a larger and larger proportion of the individuals of this nationality rise above this lowly estate, the percentage of crime among them falls off correspondingly.[300] This emphasizes once more the responsibility of the United States for some of the evil conditions for which we habitually blame the immigrants. There are two particular forms of crime which are closely associated with foreign groups in the United States. These are the Black Hand outrages and the white slave traffic. The former of these is confined almost wholly to persons of the Italian race. In some of its features it recalls the Molly Maguire occurrences of a generation earlier. In fact, the resemblance between the Irish societies and the Mafia of southern Italy was noted in a contemporary magazine article at the time of the disturbances in the anthracite region of Pennsylvania.[301] In both cases no organic connection between the societies in the new world and the old is manifest. In fact, the best judgment in regard to the Black Hand appears to be that there is no real organization in existence in America, but that individuals of Italian race use the power of the dreaded name to accomplish their own ends. Like the Molly Maguires, the Black Hand operators utilize warning letters, but they differ from them in that their purpose is often, if not usually, blackmail, which was seldom the case with the Irish society. The white slave traffic has aroused tremendous public interest during the last few years, and has been thoroughly exploited in the daily and periodical press. Only the essential features, particularly in their bearing on immigration, need to be reviewed in the present connection. Not all of the girls concerned in this business are immigrants, nor are all the persons who draw a revenue from it foreigners; yet the various investigations of the subject have demonstrated that the whole trade is fundamentally an affair of our foreign population.