"You said he'd be sending another girl--" Ritchie nodded. "So I did. And so he'll say. I suggest you beg to be excused for the moment. Tell him it will take a while for you to get over the shock of losing Sue this way." "I won't be lying," Harry murmured. "I know. And I'm sorry. Believe me, I am." Ritchie sighed again. "But you'll just have to trust me from now on." "Trust you? When you haven't even explained what this is all about?" "You've had your shock-therapy for today. Come back for another treatment tomorrow." And then Ritchie was gone, the gray uniform melting away into the gray shadows of the shrubbery above the bank. A short time later, Harry made his own way back to the center in the gathering twilight. The dusk was gray, too. Everything seemed gray now. So was Harry Collins' face, when he emerged from his interview with Dr. Manschoff that evening. And it was still pallid the next afternoon when he came down to the river bank and waited for Ritchie to reappear. The little man emerged from the bushes. He stared at Harry's drawn countenance and nodded slowly. "I was right, eh?" he muttered. "It looks that way. But I can't understand what's going on. If this isn't just a treatment center, if they're not really interested in my welfare, then what am I doing here?" "You're taking part in an experiment. This, my friend, is a laboratory. And you are a nice, healthy guinea pig." "But that doesn't make sense. I haven't been experimented on. They've let me do as I please." "Exactly. And what do guinea pigs excel at? _Breeding._" "You mean this whole thing was rigged up just so that Sue and I would--?" "Please, let's not be so egocentric, shall we? After all, you're not the _only_ male patient in this place. There are a dozen others wandering around loose. Some of them have their favorite caves, others have discovered little bypaths, but all of them seem to have located ideal trysting-places. Whereupon, of course, the volunteer nurses have located _them_." "Are you telling me the same situation exists with each of the others?" "Isn't it fairly obvious? You've shown no inclination to become friendly with the rest of the patients here, and none of them have made any overtures to you. That's because everyone has his own little secret, his own private arrangement. And so all of you go around fooling everybody else, and all of you are being fooled. I'll give credit to Manschoff and his staff on that point--he's certainly mastered the principles of practical psychology." "But you talked about breeding. With our present overpopulation problem, why in the world do they deliberately encourage the birth of more children?" "Very well put. 'Why in the world' indeed! In order to answer that, you'd better take a good look at the world." Arnold Ritchie seated himself on the grass, pulled out a pipe, and then replaced it hastily. "Better not smoke," he murmured. "Be awkward if we attracted any attention and were found together."