There was a number of friends to whom she wrote regularly, and whose relations to her may be judged from the manner in which they began their letters. "My lady of Grace," "My beloved missionary," "Dearest sister," were some of the phrases used. But her nature demanded at least one confidante to whom she could lay bare her inmost thoughts. She needed a safety-valve, a city of refuge, a heart and mind with whom there would be no reservations, and Providence provided her with a kind of confessor from whom she obtained all the understanding and sympathy and love she craved for. This was Miss Adam, who, while occasionally differing from her in minor matters of policy, never, during the fifteen years of their friendship, once failed her. What she was to the lonely missionary no one can know. Mary said she knew without being told what was in her heart, and "how sweet," she added, "it is to be understood and have love reading between the lines." Month by month she sent to Bowden the intimate story of her doings, her troubles, hopes, and fears, and joys, and received in return wise and tender counsel and encouragement and practical help. She kept the letters under her pillow and read and reread them. Never self-centred or self-sufficient, she depended upon the letters that came from home to a greater extent than many of her friends suspected. She needed the inflow of love into her own life, and she valued the letters that brought her cheer and stimulus and inspiration. Once she was travelling on foot, and had four miles of hill-road to go, and was feeling very weary and depressed at the magnitude of the work and her own weakness, when a letter was handed to her. It was the only one by that mail, but it was enough. She sat down, and in the quiet of the bush she opened it, and as she read all the tiredness fled, the heat was forgotten, the road was easy, and she went blithely up the hill. Outside the circle of her friends many people wrote to her from Scotland, and some from England, Canada, and America. Boys and girls whom she had never seen sent her letters telling her of their cats and dogs, of football, and lessons and school. With her replies sometimes went a snake skin, a brass tray, a miniature paddle, or other curio. But it was the letter, rather than the gift, that was enjoyed. As one girl wrote; "You are away out helping the poor black kiddies and people, and just as busy doing good as possible, and yet you've time to send a letter home to a little Scottish girl, a letter fragrant with everything lovely and good, that makes one try harder than ever to do right, and that fills one's heart with beautiful helpful thoughts."