She had been raised in B----, a town at the foot of a mountain chain upon whose top the grandfather of Deborah’s grandfather, Martin Kallikak Jr., had always lived. When she was a little girl, he was a very old man. She remembered being taken to drive, when a child, and seeing the old hut on the mountain, where he lived with his strange daughters, “Old Moll,” “Old Sal,” and Jemima. The dilapidated dwelling, with its windows bulging with rags, formed a picture she had never forgotten. There were in her mind floating memories of great scandals connected with these women and their lonely mountain hut. The father went by the name of the “Old Horror,” and as she remembered him, he was always unwashed and drunk. At election time, he never failed to appear in somebody’s cast-off clothing, ready to vote, for the price of a drink, the donor’s ticket. This information, coming when it did, seemed amazing and carried with it the probability of establishing the certainty of defect transmitted through five generations. But the town in question was remote and the probability of finding any living person able to give accurate information seemed so slight that nothing further was done in this direction for many months. In the meantime, the families of the fifteen brothers and sisters of Deborah’s grandfather had been worked out, and the names of several living relatives back in the mountain ascertained. The time was ripe. Appealing for a night’s lodging at the home of a retired farmer, the field worker was fortunate enough to be received. As the hostess was showing her to a room, she asked tentatively, “You have lived in B---- a long time?” “About sixty-five years,” was the pleasant reply. “So, then, you know something of most of the old families?” “There are not many old residents of B---- with whose history I am not familiar.” Then followed a few cautious questions in regard to the Kallikak family which drew forth answers that soon convinced the field worker she was on solid ground and could advance without wasting time in needless precautions. At this juncture, the supper bell rang. In the dining room the acquaintance of the host was made. When the meal was over, the couple turned their united attention to the problem put before them. “Why,” the host began, when he comprehended what was wanted, “do you know that is the worst nest you’re getting into, in the whole country? The mountains back here are full of these people; I can point out to you where every one of them lives.” Then he turned to the table and began to sketch a map of the mountain roads which must be followed next day. In the midst of this he paused, as though an idea had come to him, then he said hesitatingly, “You see, it’s really impossible for a stranger like you to find all these people. Some of them live on obscure back roads that you could hardly get at without a guide. Now, my time is of no value, and if you will permit me, I will gladly