The superstition against walking under a ladder may have originally been based on some idea of its being derogatory or dangerous to the head, though not, of course, from the fear of being struck by a falling brick.

Similarly, as shown in the article on Nai, the belief that the bodily strength and vigour were located in the hair, and to a less extent in the nails and teeth, has had a world-wide prevalence.

But this cannot have been primary, because the hair had first to be conceived of apart from the rest of the body, and a separate name devised for it, before the belief that the hair was the source of strength could gradually come into existence.

The evolution of these ideas may have extended over thousands of years.

The expression 'white-livered,' again, seems to indicate that the quality of courage was once held to be located in the liver, and the belief that the liver was the seat of life was perhaps held by the Gonds.