Pesachim 111: Saved by Verses

Don't walk between two of the following: dogs, palm trees, women (nor should these go between 2 people). The concern is witchcraft, and the protection against it seems to be recitation of one biblical verses or another. Is this all a matter of superstition? Is there any truth to it? Also, Amoraim were walking together... and their order seems to have made a difference. Plus, destruction by "Meriri" - is that a demon? Other destructive force...? Again, the Today's verses are the protective force.