When we study in the works of anthropologists the moral precepts which men have considered binding in different times and places we find the most bewildering variety. It is quite obvious to any modern reader that most of these customs are absurd. The Aztecs held that it was a duty to sacrifice and eat enemies captured in war, since otherwise the light of the sun would go out. The Book of Leviticus enjoins that when a married man dies without children his brother shall marry the widow, and the first son born shall count as the dead man’s son. The Romans, the Chinese, and many other nations secured a similar result by adoption. This custom originated in ancestor-worship; it was thought that the ghost would make himself a nuisance unless he had descendants (real or putative) to worship him. In India the remarriage of widows is traditionally considered something too horrible to contemplate. Many primitive races feel horror at the thought of marrying any one belonging to one’s own totem, though there may be only the most distant blood-relationship. After studying these various customs it begins at last to occur to the reader that possibly the customs of his own age and nation are not eternal, divine ordinances, but are susceptible of change, and even, in some respects, of improvement. Books such as Westermarck’s “History of Human Marriage” or Müller-Lyer’s “Phasen der Liebe,” which relate in a scientific spirit the marriage customs that have existed and the reasons which have led to their growth and decay, produce evidence which must convince any rational mind that our own customs are sure to change and that there is no reason to expect a change to be harmful. It thus becomes impossible to cling to the position of many who are earnest advocates of _political_ reform and yet hold that reform in our moral precepts is not needed. Moral precepts, like everything else, can be improved, and the true reformer will be as open-minded in regard to them as in regard to other matters.