Lassie - Episode135 - "Seeing Eye Dog" - Season 4, Episode 32 (04/13/1958)

Lassie finds an injured Doberman Pinscher in the woods. The dog is wearing a seeing-eye harness, but has no collar or tags. So the Martins have no idea who she is or who she belongs to until Lassie manages to track down the dog's collar.