Keeper Reid with three of his messenger dogs, trained to take messages between trenches and across dangerous stretches of the front line during the First World War. The dog on the left is called Tweed, who was singled out for praise by Reid, as she ran messages between Battalion Headquarters and Transport Lines under heavy shell fire. He was a Highland sheep dog (but clipped for ease of movement) and although sensitive to begin with, was trained to a very high standard.