No instruments had ever been developed by the Graken with which to ascertain the facts about a planet from a distance greater than a few thousand miles. Thus, to check on size, gravity, atmosphere, animal life and so forth, the patrols were forced to scan a world from just beyond its limit of attraction. One possible haven out of each hundred thousand planets checked was an excellent average, one in half a million more than usual. Some worlds accepted were smaller, with less gravity, others had certain differences atmospherically; but the Graken were an adaptable breed, and readily conformed to such changes. The one male Graken in three who was not taken for saucer duty became a shepherd, a breeder of food animals, or a scientist. The females bred and raised their offspring and bred again; their fertile life extended over the years from fourteen to eighty-five, their gestation period was four months. The race was prolific.... The need for worlds was continually urgent. And Terra was an almost perfect duplication of the Graken's prototype home planet. The last development in the Graken's marauding through the reaches of space was the actual kidnapping of the new worlds, the theft of entire planets and their transportation through sub-space into the star system Lluagor. This had been conceived and perfected only a few generations before. The chain of Graken-inhabited globes had reached the sum of fifty-three, and travel between them had become tedious, arduous, and sometimes dangerous, for the ships used for ordinary traveling were fewer and of older patterns than the patrol vessels. The Graken found their communal minds drifting into widened channels, as direct contact became less and less. The pressing need was for a single system of worlds ranged about one star, in which travel would be easy and frequent. They therefore devised the kidnapping principle. First every planet unfit for Graken life in the system Lluagor was exploded, leaving only two balls spinning about the sun Tsloahn. Then, one by one, the new Graken planets were brought through sub-space and dropped into the home system. This was done by a method which could not be made completely clear by the captive green man; the basic idea of which, however, was easy to comprehend: * * * * *