"_I_ don't understand," said Mrs. Stanton, breaking into sudden tears. "I just don't understand why Martin should behave this way! Why should he just sit there with his eyes closed and ignore everybody? Why should he ignore his mother and his brother? Why?" The doctor comforted her in a warmly professional manner, then, as her tears subsided, he said, "We don't understand all the factors ourselves, Mrs. Stanton. At first glance, Martin's reactions appear to be those one would expect of schizophrenic withdrawal. But there are certain aspects of the case that make it unusual. His behavior doesn't quite follow the pattern we usually expect from such cases as this. His extreme physical disability has drastically modified the course of his mental development, and, at the same time, made it difficult for us to make any analysis of his mental state." _If only_, he added to himself, _she had followed the advice of her family physician, years ago. If she had only put the boy under the proper care, none of this would have happened._ "Is there _any_thing we can do, Doctor?" she asked. "We don't know yet," he said gently. He considered for a moment, then said: "Mrs. Stanton, I'd like for you to leave both of the boys here for a few days, so that we can perform further tests. That will help us a great deal in evaluating the circumstances, and help us get at the root of Martin's trouble." She looked at him with a little surprise. "Why, yes, of course--if you think it's necessary. But ... why should Bart stay?" The doctor weighed his words carefully before he spoke. "Bart will be what we call a 'control', Mrs. Stanton. Since the boys are genetically identical, they should have been a great deal alike, in personality as well as in body, if it hadn't been for Martin's accident. In other words, our tests of Bart will tell us what Martin _should_ be like. That way, we can tell just how much and in what way Martin deviates from what he should ideally be. Do you understand?" "Yes. Yes, I see. All right, Doctor--whatever you say." After Mrs. Stanton had left, the psychiatrist sat quietly in his chair and stared thoughtfully at his desk top for several minutes. Then, making his decision, he picked up a small book that lay on his desk and looked up a number in Arlington, Virginia. He punched out the number on his phone, and when the face appeared on his screen he said, "Hello, Sidney. Busy right now?" "Not particularly. Not for a few minutes. What's up?" "I have a very interesting case out here that I'd like to talk to you about. Do you happen to have a telepath who's strong enough to take a meshing with an insane mind? If my suspicions are correct, I will need a man with an absolutely impregnable sense of identity, because he's going to get into the weirdest situation I've ever come across." _[14]_