"The experimentation had been designed to provide Kalechi's master-biologists with models towards which to work. They proposed to utilize the high mutability of their species to develop a Satog type that would be the exact physical counterpart of a human being and could live undetected on our worlds for the several years required to prepare for the attack. They were amazingly successful. Each group of cells in the long series which began moving towards an approximation of the human pattern was developed only far enough to initiate the greatest favorable shift possible at that point in its genetic structure. Cell generations may have followed each other within hours in this manner, for over six decades. "The goal of the experiment, the last generation issued in Kalechi's laboratories, were Satog copies of embryonic human beings. This stage was comprised of approximately twelve hundred individuals who were now permitted to mature and were schooled individually in complete isolation by Satog teachers. They were indoctrinated with their purpose in life ... the destruction of our populations ... and trained fully in the manner of accomplishing it. "Eventually, each was shipped to a Federation world. Cover identities as obscure Federation citizens with backgrounds and records had been prepared. The final instructions given these agents were simple. They were to do nothing to draw attention to themselves, make no attempt to contact one another. They were to create their stocks of lethal organisms, provide methods of distribution and, on a selected day, three Federation years away, release the floods of death." * * * * * The voice paused briefly, went on. "It is a sobering reflection that this plan--an attack by a comparatively minor race with one specialized skill on the greatest human civilization in history--might very well have been appallingly successful. But the Great Satogs failed, in part because of the very perfection of their work. "From the human beings on board Ohl Cantrall's captured survey ship the Satog scientists selected Cantrall himself and two female technicians on his staff as the models to be followed in developing Kalechi's pseudohumanity. In the twelve hundred members of the group sent to the Federation ninety years later, these three identity-patterns are recognizable. They appear in varying degrees of combination, but an occasional individual will show only one or the other of the three patterns involved.