The twins were as like as two peas, and to preserve their identity the usual expedient was tried of decorating them with ribbons of different hue. But when, at three years of age, they were detected in the very natural act of swapping ribbons, I, as the family physician, was called in; then Jack's identity was fixed with a tattooed dot of india ink on his left arm, and Jim's with a corresponding dot on his right. Their mother was mostly concerned with their pain and protesting squalls, their father with my wonderful ingenuity, and I with the rebellious, yet imperious, thought that, according to the eternal fitness of things, I should have been the father of these two beautiful boys. Their father was about my age, twenty-five, and a weakling; one who, as a boy, could never catch a ball nor throw one straight; who never learned to swim, and preferred girls for playmates; who, as a youth, could not dress himself without assistance; who never, in his whole lackadaisical life, had an original thought or took the initiative in any proceeding; and why that splendid, healthy-minded, dark-eyed girl of seventeen should choose him out of a host of suitors was beyond my comprehension at the time. Later, I understood; somewhat weakly sexed at that age, but largely endowed with the maternal instinct (she played with dolls until within a year of her marriage), she pitied his helplessness and married him to mother and protect him. And from this pair, so utterly diverse, Mother Nature produced two perfect specimens of humanity, and rested. After their arrival the parents drifted apart, and from sheer incompatibility were divorced when the boys were seven years old. They went to their original homes at opposite sides of the town, each taking a twin; for the asinine judge, unable to decide in favor of either, had, Solomon-like, so conditioned the divorce. Their grief was heart-rending--equaled only by that of the mother, as I, in my professional relation to each home, had full opportunity to judge. But time softened this grief in all of them, and brought about in the mother a state of mind exceedingly valuable and gratifying to me. In a year from the divorce she became my wife. So far I had observed the development of the twins as a physician, noting that the measles, mumps, croup, and other childhood ailments came to both at the same time, and, as a physician, ascribing it to bodily contagion. But now, still a physician to each, I took note of other concurrent happenings that spoke of mental contagion as well. I was called to Jim late one afternoon by the agitated father, and found him in a strange mental condition, crying and laughing, and again storming in an ecstasy of rage at the house-dog, a gentle, harmless collie and a former pet, against whom he had conceived a violent hatred. He had attacked and nearly killed him with a club.