The tane unto the tither did say,

seriously ill and Marie LeGarde frighteningly weak and exhausted, I couldn't remain any longer. Had I been made of tougher stuff, or even had I not been a doctor, I might have brought myself to recognise that both Marie LeGarde and Theodore Mahler were expendable pawns in a game where the stakes, I was now certain, were far greater than just the lives of one or two people. I might have held everybodyor the major suspects, at leastat gunpoint until such time, twenty-four hours if need be, as Hillcrest did come up. But I could not bring myself to regard our sick passengers as expendable pawns. A weakness, no doubt, but one that I was almost proud to share with Jackstraw, who felt exactly as I did. That Hillcrest would come up eventually I felt pretty sure. The dumping of the sugar in the petrolI bit my lips in chagrin whenever I remembered that it had been I who had told them all that Hillcrest was running short of fuelhad been a brilliant move, but nothing more, now, than I had come to expect of men who thought of everything, made every possible provision against future eventualities. Still, even though furiously angry at the delay, Hillcrest had thought he could cope with the situation. The big cabin of the Sno-Cat was equipped with a regular workshop with tools fit to deal with just about every mechanical breakdown, and already his driver-mechanic-1 didn't envy him his murderous task even though he was reportedly working behind heated canvas apronshad stripped down the engine and was cleaning pistons, cylinder walls and valves of the unburnt carbon deposits that had finally ground the big tractor to a halt. A couple of others had rigged up a makeshift distillation unita petrol drum, almost full, with a thin metal tube packed in ice leading from its top to an empty drum. Petrol, Hillcrest had explained, had a lower boiling point than sugar, and when the drum was heated the evaporating gas, which would cool in the ice-packed tube, should emerge as pure petrol. Such, at least, was the theory, although Hillcrest didn't seem absolutely sure of himself. He had asked if we had any suggestion, whether we could help him in any way at all, but I had said we couldn't. I was tragically, unforgivably wrong. I could have helped, for I knew something that no one else did, but, at the moment, I completely forgot it. And because I forgot, nothing could now avert the tragedy that was to come, or save the lives of those who were about to die. My thoughts were black and bitter as the tractor roared and lurched and camera digital direct printing clattered its way south-west by west under the deepening darkness of a sky that was slowly beginning to fill with cloud. A dark depression filled me, and a cold rage, and there was room in my mind for both. I had a strange fey sense of impending disaster, and though I was doctor enough to know that it was almost certainly a psychologically induced reaction to the cold, exhaustion, sleeplessness and hungerand a physical reaction to the blow on the headnevertheless I could not shake it off: and I was angry because I was helpless. I was helpless to do anything to protect any of the innocent people with me, the people who had entrusted themselves to my care, the sick Mahler and Marie LeGarde, the quiet young German girl, the grave-faced Margaret Rossabove all, I had to admit to myself, Margaret Ross: I was helpless because I knew the murderers might strike at any time, for all I knew they might believe that Hillcrest had already told me all I needed to know ana that I was just waiting my chance to catch them completely off guard; on the other hand they, too, were almost certainly just biding their time, not knowing how much I knew, but just taking a calculated gamble, letting things ride as long as the tractor kept moving, kept heading in the right direction, but prepared to strike once and for all when the time came: and, above all, I was helpless because I still had no definite idea as to who the killers were. For the hundredth time I went over everything I could remember, everything that had happened, everything that had been said, trying to dredge up from the depths of memory one single fact, one isolated word that would point the finger in one unmistakable direction. But I found nothing. Of the ten passengers Jackstraw and I had with us, six of them, I felt certain, were almost beyond suspicion. Margaret Ross and Marie LeGarde were completely beyond it. The only things that could be said against Mrs Dansby-Gregg and Helene was that I hadn't absolute proof of their innocence, but I was certain that such proof was quite unnecessary. United States senators, as recent bribery and corruption cases had lamentably shown, had as many human failingsespecially cupidityas the next man: but, even so, the idea of a senator getting mixed up with murder and criminal activities on this massive scale was too preposterous to bear further examination. As for Mahler, I was quite aware that being a diabetic didn't bar a man