But it was with a distinct sense of relief that they saw the end of that forest ahead of them. Unconsciously they hurried their steps until they were almost trotting. For the balance of their trip Jon was strangely acquiescent as Jak became more and more engrossed in the strange plant life of this world Three. He knew that this was Jak's dish, and he was perfectly willing to defer to the elder's knowledge and desire to learn. His main concern was to keep his brother from overloading himself with specimens, or from loitering too much. Jak had been especially studying the soil here, Jon noticed, and finally he asked about it. "Notice one peculiar thing about this planet?" "What's on your mind?" "The total absence, as far as we've seen, of any sort or type of protoplasmic life," Jak reported. "Hey, that's right, though I hadn't thought of it before. Our examination from the air, I remember now, showed no animals, birds or people. Plenty of vegetation, though." "Yes, it has everything in that line. I wonder, though...." He paused, and he grew thoughtful. "Wonder what?" "How those plants can grow, without any worms or ants or anything to loosen and irrigate the soil, and no animals or birds to make fertilizers, or bees or butterflies or anything to carry pollen?" Jon shrugged. "Wouldn't have the foggiest. That's your line, not mine. But they must do it some way--there's sure lots of plant life here." But Jak was still shaking his head in puzzlement as they finally returned to the ship. It was quite dark outside when the boys went into the control room after dinner. Jon went over to the window-ports, while Jak began working with his plant specimens. "Jak, come here," Jon called after a moment or two. The elder, prompted by the curious urgency in his brother's voice, left his specimens and ran to the other's side. "What're those things?" Jak stared through the port in amazement. Outside, drifting across the clearing, were nearly a dozen large, spherical things like ghostly white balloons. They must have been almost a yard in diameter, and by straining their eyes the boys could see tentacles or tendrils of some sort depending from the bottom surfaces. "Gosh, never saw anything like those. Let's go out and see what they are." "Let's not and say we did," Jon retorted. "I want to find out more about them first." He went over to the control panel and switched on the searchlight, as well as the pilot's visi-screen. Looking into the latter, he was able to direct the light so it shone on a couple of the floating balls. Jak was studying the plants--for so he believed them to be--more carefully, now that they were lighted. But after a moment he yelped excitedly, "Hey, they're deflating. Must be the light does it." Jon was watching them in his screen. "Yes, I see now. What causes it?" "I don't know," Jak answered sadly and absently. "But I sure want to know. How's about covering me while I go out and see if I can get one?"