They returned, to report that the second herd of unicorns had broken down the walls and ripped the interior of the stockade into wreckage. Much of the food and supplies had been totally destroyed. Lake sent them back twice more to bring everything, down to the last piece of bent metal or torn cloth. They would find uses for all of it in the future. * * * * * The cave system was extensive, containing room for several times their number. The deeper portions of the caves could not be lived in until ventilation ducts were made, but the outer caves were more than sufficient in number. Work was begun to clear them of fallen rubble, to pry down all loose material overhead and to level the floors. A spring came out of the ridge not far from the caves and the approach to the caves was so narrow and steep that unicorns could scramble up it only with difficulty and one at a time. And should they ever reach the natural terrace in front of the caves they would be too large to enter and could do no more than stand outside and make targets of themselves for the bowmen within. Anders was in charge of making the caves livable, his working force restricted almost entirely to women and children. Lake sent Barber out, with a small detachment of men, to observe the woods goats and learn what plants they ate. And then learn, by experimenting, if such plants could be safely eaten by humans. The need for salt would be tremendously increased when summer came. Having once experienced a saltless two weeks in the desert Lake doubted that any of them could survive without it. All hunting parties, as well as Barber's party, were ordered to investigate all deposits that might contain salt as well as any stream or pond that was white along the banks. The hunting parties were of paramount importance and they were kept out to the limits of their endurance. Every man physically able to do so accompanied them. Those who could not kill game could carry it back to the caves. There was no time to spare; already the unicorns were decreasing in numbers and the woods goats were ranging farther and farther north. At the end of twenty days Lake went in search of Barber and his party, worried about them. Their mission was one that could be as dangerous as any hunting trip. There was no proof that humans and Ragnarok creatures were so similar as to guarantee that food for one might not be poison for the other. It was a very necessary mission, however; dried meat, alone, would bring grave deficiency diseases during the summer which dried herbs and fruits would help prevent. When he located Barber's party he found Barber lying under a tree, pale and weak from his latest experiment but recovering. "I was the guinea pig yesterday," Barber said. "Some little purple berries that the woods goats nibble at sometimes, maybe to get a touch of some certain vitamin or something. I ate too many, I guess, because they hit my heart like the kick of a mule."