This book contains Volumes 1 and 2 of the original work. The beliefs, customs and institutions of tribes in a low degree of civilization are our only clue to those of a more archaic condition no longer in existence. They are evolved from them and are the outgrowth of ideas which underlay them. When we find a belief, a custom or an institution, still more when we find a connected series of beliefs, customs and institutions, over spreading the lower culture, we may reasonably infer its root in ideas common to mankind and native to the primitive ancestral soil. The advance of even the most backward from primeval savagery has been so great that a large harvest of these ideas is not to be expected. But, the researches yielded enough, it is hoped, to afford a satisfactory solution of, among others, the problem under consideration in this volume.