"Nothing is more unsatisfactory than to attempt to define Indo-European society on the assumption that the Indo-Europeans knew only what can be ascribed to them on con- clusive evidence. Ex hypothesi, there were great dispersals of peoples from the original home, and those who wondered away were unquestionably constantly intermingling with other peoples . . . and it is not to be wondered at that in new surroundings new words were employed; still less can it be a matter of surprise that peoples which ceased to be in contact with natural features soon dropped the names which had become use- less."