It has often been observed that cultural traits are exceedingly tenacious and that features of hoary antiquity survive until the present day. This has led to the impression that primitive culture is almost stable and has remained what it is for many centuries. This does not correspond to the facts. Wherever we have detailed information we see forms of objects and customs in constant flux, sometimes stable for a period, then undergoing rapid changes. Through this process elements that at one time belonged together as cultural units are torn apart. Some survive, others die, and so far as objective traits are concerned, the cultural form may become a kaleidoscopic picture of miscellaneous traits that, however, are remodelled according to the changing spiritual background that pervades the culture and that transforms the mosaic into an organic whole. The better the integration of the elements the more valuable appears to us the culture. I believe that it may be said that the coherent survival of cultural features that are not organically connected is exceedingly rare, while single detached elements may possess marvellous longevity. * * * * * In the present book the problem of growth of individual art styles will be touched upon only incidentally. Our object is rather an attempt to determine the dynamic conditions under which art styles grow up. The specific historical problem requires much fuller material than what we now possess. There are very few parts of the world in which we can trace, by archaeological or comparative geographical study, the growth of art styles. Prehistoric archaeology in Europe, Asia, and America shows, however, that, as general cultural traits are in a constant state of flux, so also do art styles change and the breaks in the artistic life of the people are often surprisingly sudden. It remains to be seen whether it is possible to derive generally valid laws that control the growth of specific art styles, such as Adama van Scheltema has tried to derive for North European art.[4] With increasing technical skill and perfection of tools, changes are bound to occur. Their course is determined by the general cultural history of the people. We are not in a position to say that the same tendencies, modified by local historical happenings, reappear in the course of art development everywhere. [4] Die altnordische Kunst, Berlin, 1923.