So it is in psychical anthropology. A department of it, Folklore, is taken up with such survivals, and strange are its revelations! Our Christmas dinner is a reminiscence of a cannibal feast at the winter solstice. The dyed Easter egg is a relic of a myth of the dawn older than the Pyramids. In strictly scientific language evolution is not always synonymous with progress. It means simply change or transformation within the limits of physiological laws—that is, that such changes tend, on the whole, to the preservation of the individual or do not conflict with it. Life is the criterion of evolution. But the application of this standard is not always easy. The most salient variation is not necessarily the most important. Again, a variation admirably suited to a given mode of existence may be unfriendly to development by unfitting the stock for later and inevitable changes of environment. In the psychical ethnic life there are, however, a limited number of characteristics, the symmetrical development of which cannot fail to bring out all the latent powers of the group in the struggle for its independent existence; and, conversely, their neglect or faulty cultivation will surely pave the way to debility and disappearance. They are the primary factors of progressive variation in ethnic psychology. The list of them is as follows: 1—Remembrance. 2—Industry. 3—Inventiveness. 4—Adaptability. 5—Receptiveness. 6—Forethought. They are all essential to ethnic progress; though the special cultivation of one or the other must be dictated by the circumstances. The development must be in relation to the inner (mental) and outer (physical) demands upon the group, if it is to make the best of its life. They are the physiological elements of collective mental growth, standing in relation to it as do proper food, exercise, cleanliness, and the other hygienic methods to bodily health and strength. 1. _Remembrance._—Knowledge is of no avail unless it is remembered. Experience may become prophetic, but if its words are forgotten, of what use is its wisdom? Hence the rudest savages seek means to strengthen their recollection of events and ideas. The Australian has his message stick, the Peruvian his knotted string (_quipu_), the Chippeway his _meday_ club,—all to help preserve tradition, ritual, knowledge, in some form. Whatever technical process was devised to shape a war club, or to minister to the sense of beauty by adornment, whatever laws were framed to regulate the clan, whatever secrets were learned from nature, became of value to the group only in so far as the faculty of memory and the means of remembrance were cultivated.