This is a typical problem that occurs in very old wiring. The isulation is deteriorated from a combination of heat caused by the light fixture and inferior insulation that is found on old wiring.
This homeowner built a new wall and instead of moving the box to the new wall they just extended the wires and screwed the switch to the drywall. (Very Dangerous)
This is an example of a homeowner adding a receptacle using white extension cord. It was found when they remodeled there bathroom.
This is a splice that someone did using only electrical tape and no wire nuts. This was causing outlets on the second floor of this house to not work.
This wire had beed cut at some time and once again repaired with electric tape only, and no box!