We are accustomed to designate the crude supernatural ideas of savage and barbarous peoples as cults, and every cult will be found on examination to be composed of two complemental parts, known as mythology and ritual. Around the former group themselves the various beliefs regarding the supernatural, and about the latter the processes by which man approaches and influences these supernal conceptions. This bifid strand runs through all supernatural ideas, from those of the savage to the civilized man. As nature has thus united them, they must always be considered together in scientific studies. We have seen in one of the previous lectures of this course how certain arts of man are affected by environment. I shall endeavor to show a connection between ceremonial practices and climatic conditions, which are, I take it, essential factors of environment. For an illustration, I have chosen the influence of an arid climate upon the ritual of one cluster of American Indians. There are certain common components of all cults which are as widely spread as the races of man and exist independently of surroundings, while there are others which are profoundly affected by environment. Our subject especially deals with the latter, and as the ritual is capable of more exact scientific analysis, I have in mind to discuss the modifications in it which can be traced to purely climatic causes. To simplify the elements of the problem we must choose not only a primitive form of ritual, but also as far as possible one which has been but slightly modified by the introduction of foreign influences, and hence other environments. We must avoid as much as possible complexity due to composition. It is a very difficult task to determine the aboriginal cults of any primitive people, for modifications resulting from contact with other races are present almost everywhere we turn. Every cluster or grouping of men known to me is composite in its character. Yet the task is not wholly hopeless or beyond our powers. The work before the American student is facilitated by the fact that we have still living in our country surviving members of the American race who, on account of isolation, have been slightly modified by foreign influences. I wish this afternoon to call your attention to one of these, and to discuss the influences which environment has exerted on their ritual.