But some kinds of traditions are more easily delivered than others. A custom which requires the co-operation of a number of persons is less easily transmitted than one which requires only the co-operation of two, or which can be performed by one person alone. A long and complicated ceremony is less easily transmitted than a short and simple one. A nickname passes from mouth to mouth more rapidly than a proverb, a proverb more rapidly than a story, a story than a song. In short, the more complex the tradition the greater the difificulty of transmission, and the more it depends on frequent repetition and other circumstances calculated to impress it on the memories of the recipients. Thus, a story or a song is repeated over and over by mother to child. The words, hardly comprehended at first, become clear as the child's understanding grows, and are not only involved in his earliest reminiscences, but probably rendered indelible by reiteration by others in his hearing, or by himself to younger children, from time to time throughout his life. Few traditions, and as a rule those only of the simplest kinds, are transmitted by a single communication. It follows that traditions are not often transmitted by casual intercourse. Some kinds of traditions, indeed, are not communicated even during years, and perhaps a whole lifetime, of intercourse of an intimate character. In some cases a formal initiation ceremony, which is itself a tradition, and which confers upon the initiated certain rights, carrying with them, of course, corresponding liabilities, has to be undergone. And in many more cases the custodians of the tradition, if I may call them so, cannot be persuaded to communicate it until they are assured of sympathy in the recipient. Apart from modern scientific inquirers, this sympathy can, in general, only be shown by one who is at no great distance of culture, and who therefore is familiar with ideas and practices not very widely different. Such an one can best receive and assimilate, and in his turn transmit, the tradition.
These considerations exhibit the difficulties of transmission from a foreign source. It cannot be denied that there is another side to the picture. The conditions for transmission, even of recondite and carefully guarded traditions, must have been fulfilled again and again in the world's history. Conquest followed by permanent settlement among the conquered people, the inter-
