But these simple compounds with a single foreign theme do not complete the tale. When once they were formed, they in turn had each a history of its own, with infinite possibilities of absorbing traits from other stories or even entire themes. In the case of the latter, a reason could always be found in such points of contact as I have already mentioned, or so I believe, if the material were sufficient for proper comparison. In this way arose the complicated types treated in chapter six, where the manner of combination is readily seen. [274] Sometimes, it is probable, subtraction has taken place as well as addition, but apparently only when it has not involved the disentangling of various traits. For example, many variants have been noted where one of the two most striking features of our central theme, the burial of the dead debtor, has disappeared; yet in every case the rest of the plot has remained unimpaired. The more complicated the variant, the better able is the investigator to place its kinship to other variants, provided that he has the requisite material and the patience to follow up the clues that every such labyrinth affords. The most striking facts of general import to the study of folk-narrative that have developed in the course of this prolonged consideration of The Grateful Dead may be briefly summarized in conclusion. It has been shown once again that the story has an organic life of its own, whether it comes from the East or the West, whether it be founded upon some fact of social custom or belief, or on the imaginings of a moralist of antiquity. [275] Once started, it will go its way through divers lands and ages, yet retain unaltered the essential features of its plot. Call it story-skeleton, or better, living organism, it always keeps its structural integrity, no matter whether told as a pious legend or a conte a rire. Of no less importance than this is the fact that whatever serious changes take place in its form are not fortuitous, mere whimsical alterations due to the fancy of story-tellers, but are due to capabilities of expansion or combination in the plot itself. Whenever two themes with points of resemblance, or contact come into the same region, they are in the long run pretty certain to unite, each retaining its individuality, but merging in the other. This principle is well illustrated in the history of The Grateful Dead. The marriages of stories seem never to be merely for convenience, except in the hands of conscious writers, but to be the result of attraction and real compatibility. That, I take it, is why and how narratives develop.