That the simple motive of The Grateful Dead was not exhausted by the two remarkable combinations just treated, that it retained its individuality and independence, is shown by the various minor combinations discussed in the third chapter. It is altogether probable that other examples of such simple compounds as those containing The Swan-Maiden, Puss in Boots, and a story like that told of Pope Gregory [273] are in existence, and may be found by later study. One can speak only with reference to material at command. Very likely other combinations than those treated here are in existence and may also appear, either in sporadic cases or in groups. But, the reader may ask, if the motive is found in so many compounds, both with and without The Poison Maiden and The Ransomed Woman, why does it not occur more frequently, at least in folk-literature, without combination? To this I should reply that the story is an ancient one, which has many points of correspondence with other themes. By reason of these traits it has absorbed, or has been absorbed by, these other tales, until now it is difficult to find examples of the simple form. A thousand years ago, or some such matter, they may, indeed, have been frequently retold by the firesides of Europe, though now they are practically unknown. The constant tendency of folk-tales to change from simplicity to complexity would in time cause the pure theme to be generally forgotten. Nevertheless, its existence could be proved, even though no example still remained, for the various independent compounds would be inexplicable on any other theory. In the case of The Grateful Dead, the tales, to which it has been joined, have been so interwoven with its substance that it is quite impossible to believe, for example, that the combination with The Ransomed Woman proceeded from that with The Poison Maiden.