When Mr. McKern wrote to suggest that I might wish to add a word to the discussion of those cultures which may show some indications of Old World contacts, my first impulse was to burst out with a long list of analogies in support of such an hypothesis. After thinking it over, however, I realized that this had often been done in the past without success, and it occurred to me that it might be more pertinent to try to explain how one diffusionist has reached his present estate, and what symptoms to look for in a person who has been subjected to this form of contagion.