Or what passed for breakfast. It was little enough, heaven knew – coffee, crackers and the contents of a couple of corned beef tins shared among the twelve of us, the lion's share going to Theodore Mahler. That left us with only four more tins of beef, four cans of vegetables, about ten pounds of dried fruit, a little frozen fish, a small tin of biscuits, three packets of cereal and – it was the only thing apart from coffee of which we had an adequate supply – over twenty tins of Nestle's unsweetened milk. We had, of course, seal meat for the dogs – Jackstraw thawed some out for them over the stove while we had breakfast – and the fried meat of young seal is palatable to a degree. But the dogs had first claim on that. It was more important to preserve their strength than our own: should the engine of the Citroen break down completely, our last hope lay with the dogs.

Breakfast over and the dogs fed, we started off just before moonset, Corazzini driving, with the long trailing plume of our exhaust vapour, milk-white but thick as smoke in that bitter air, stretching out far behind us, bar-straight, almost as far as the eye could see in the waning light of the moon. I had arranged that the drivers should change over every fifteen minutes – as long a period as any person could stand in that unheated and largely unprotected cabin. I had heard of a case in the Antarctic where a driver had sat so long in an exposed tractor that his numbed and frozen fingers had locked so immovably that the steering-wheel had had to be unbolted and brought inside still clutched in the driver's grasp before the hands could be thawed sufficiently to release the wheel: I didn't want anything of that kind happening to us.

As soon as we were under way I had a look at Mahler, and his appearance certainly did nothing to inspire any great confidence in his chances. Even although he was fully dressed, lying in an eiderdown sleeping-bag that was zipped all the way to his chin, and covered in blankets, his pinched face was a mottled blue-white and he was shaking continuously with the cold, a handkerchief between his teeth to prevent their chattering. I reached for his wrist. The pulse was very fast, though it seemed strong enough: but I couldn't be sure, so much skin had been sloughed or burnt off in the past two or three hours that I'd lost all sensitivity in my fingertips. I gave him what I hoped was an encouraging smile.

"Well, how do you feel, Mr Mahler?"

"No worse than anyone else, I'm sure, Dr Mason."

"That could still be bad enough. Hungry?"

"Hungry!" he exclaimed. "Thanks to the generosity of these good people here, I couldn't eat another crumb."

It was typical of what I had come to expect of this gentle Jew in the past few hours. Despite the relatively generous amount of food he'd had for his breakfast, he'd wolfed it all down like a famished man. He was hungry, all right: his body, lacking the insulin to break down the mounting sugar in his blood, was crying out for nourishment yet unable to find it no matter what his food intake was.

"Thirsty?"

He nodded. Perhaps he thought he was on safe ground there, but it was another and invariable symptom, of the developing acuteness of his trouble. I was pretty certain, too, that he had already begun to weaken, and I knew it wouldn't be long before he began to lose weight rapidly. Indeed, he already looked thinner, the cheekbones were more prominent, than even thirty-six hours ago. But then that was true of all the others also, especially Marie LeGarde: for all her uncomplaining courage, her determined cheerfulness, she now looked more than old: she looked sick, and very tired. But there was nothing I could do for her.

"Your feet?" I asked Mahler. "How are they?"

"I don't think they're there any longer," he smiled.

"Let me see them," I asked sharply. He protested, but I overruled him. One look at that dead-white ice-cold flesh was enough.

"Miss Ross," I said. "From now on you are Mr Mahler's personal Gunga Din. We have a couple of rubber bags in the sled. I want you to keep these alternately filled just as soon as you can get water heated – unfortunately, it takes a long time to melt that damned snow. They're for Mr Mahler's feet." Again Mahler protested, objecting to what he called 'This babying', but I ignored him. I didn't want to tell him, not yet, that frostbite in the feet of an untreated diabetic could mean only one thing: gangrene and amputation, at the least. Slowly I looked round the occupants of the tractor cabin and I think that had I known for certain who the person responsible for all this was, I would have killed him without compunction.

Just then Corazzini came in. After only fifteen minutes at the wheel of the tractor he had just yielded to Jackstraw he was in a pretty bad way. The bluish-white bloodless face was mottled with yellow frostbite blisters, his lips were cracked, the fingernails were beginning to discolour and his hands were in a shocking mess. True, Jackstraw, Zagero and I were little better, but Corazzini was the only one who had driven in that intense cold: he was shaking like a man with malarial fever, and from the way he stumbled up the steps I could see that his legs were gone. I helped him to a vacant seat by the stove.

"Feel anything below the knees?" I asked quickly.

"Not a damned thing." He tried to smile, but the effort was too painful, the blood started to well again from the open cuts on his lips. "It's pretty vicious out there, Doc. Better rub the old feet with some snow, huh?" He stooped and rumbled uselessly at laces with his numbed and bleeding fingers, but before he could move Margaret Ross was on her knees, easing off his boots with gentle fingers. Looking down at that slight figure lost beneath the bulky layers of clothing, I wondered for the hundredth time how I could ever have been crazy enough to believe about her all the things I had done.

"In your own idiom, Mr Corazzini," I said, "snow is strictly for the birds. Just an old wives' tale as far as these temperatures are concerned. You'd be better rubbing your skin off with emery-paper." At 70° below, snow had the hard crystalline structure of sandstone, and, when rubbed, granulated into a gritty white powdery sand. I nodded to one of the snow-buckets on the stove. "When the temperature there reaches 85°, stick your feet in it. Wait till the skin turns red. It won't be pleasant, but it'll work. If there are any blisters I'll puncture and sterilise them tomorrow."

He stared at me. "Is that sort of thing going to go on all the time, Doc?"

"I'm afraid so."

And it did go on for all the time – or for the next ten hours, at least, during which time the temperature dropped down to the low seventies, halted and began its slow, ever so slow, upward swing again. Ten hours while the snow-buckets were never off the stove, ten hours while Mrs Dansby-Gregg, her maid, Helene and, later on, Solly Levin held blow-torches against the sides of the buckets to hurry up the melting and heating process, ten hours while we drivers suffered the regularly recurring pounding agony of circulation returning to our frozen limbs, ten hours during which we began to build up an almost pathological dread of the moment when we must again plunge our feet into hot water, ten hours during which Mahler grew steadily weaker and Marie LeGarde, falling silent for the first time, slipped down and lay huddled in a corner, eyelids closed, like one already dead. Ten hours. Ten interminable indescribable hours of suffering borrowed from purgatory. But long before these ten hours were up something happened to change the picture completely.

At noon we halted the tractor. While the women were heating up soup and using a blow-torch to thaw out two cans of fruit, Jackstraw and I rigged up the radio transmitter, strung out an antenna and started triggering out our GFK call-sign. Normally, on these hand-cranked eight-watt jobs, a morse key was used for transmission while reception was by a pair of earphones, but thanks to a skilful improvisation by Joss who knew how hopelessly awkward morse was for everyone in the party except himself, the set had been rigged so that the key was used only for the call-up sign. After the link was made, a hand microphone could be used for transmission: and simply by throwing the receiving switch into the antenna lead, the microphone was transformed into a small but sufficiently effective loudspeaker.