The degree of civilization, or, more accurately speaking, of savagery which characterized these as a whole necessarily varied to a great extent in the case of each particular tribe. Nevertheless, from the comparatively high culture of the Incas down to the most intellectually submerged people of the forests and swamps, there were certain characteristics held in common by all. This applied not only to a marked physical likeness which stamped every dweller in the great Continent, but to customs, religious ceremonies, and government as well. Concerning the origin of the South American Indians interminable disputes have now raged for generations, but that in the case of all the various tribes the origin was the same has never, I think, been controverted. The most common theory concerning the origin of the South Americans is that this was Mongolian.