IN the search for the causes of various social phenomena characteristic of the Jews, most writers have been content to give 'race influence' a prominent place. The effects of the physical and social environment on the individual, or group of individuals, have been neglected. Once that remarkable cloak for our ignorance, 'race,' had served the purpose of explaining easily the causation of a given social fact, it was an easy matter to rest content with this explanation. It was repeatedly alleged that the Jews, though scattered in all the regions of the habitable globe, subjected to all varieties of climatic, social and economic conditions, nevertheless present everywhere the same characteristics with a remarkable uniformity. Demographic and social phenomena, such as fertility, mortality, marriage rates, illegitimacy, intermarriage, divorce, criminality, etc., were all attributed to ethnic origins, to Semitic influences.
Anthropological research has, however, revealed that there is no such thing as Jewish race, that ethnically Jews differ according to the country and even the province of the country in which they happen to live, just as catholics or protestants in various countries differ from each other. It was shown that there are various types of Jews, tall and short, blond and brunette, brachycephalic and dolichocephalic, etc.; and that all these types appear to correspond to the types encountered among the non-Jewish population among which they live. 'Race' can, consequently, not be the only cause of the demographic and social peculiarities said to be characteristic of the Jews. Other causes are to be sought for.
In the following studies statistical data of recent censuses in various European countries have been utilized in an attempt to find primarily whether the Jews do actually present uniformly, as has been alleged, similar social and demographic phenomena in every country, irrespective of difference of the physical and social environment. While the ethnic factor has not been neglected, still, in cases in which race influence is not sufficient to explain satisfactorily a social or demographic fact, or is in direct contradiction with actual conditions, the effects of the physical environment and of social conditions have been looked into. The author assumes that if an ethnic cause exclusively underlies a given social fact observed among the Jews, then we should