But it takes time, gentlemen, a great deal of time. You can't compress the natural changes of twenty centuries into a couple of years: neither mind nor body can stand it. You can try, of course, and such is the fantastic resilience and toughness of man that he can tolerate it, for extremely short periods. But the limit, the saturation capacity for adaption is soon reached. Push men beyond that limit and anything can happen. I say 'anything' advisedly, because we don't yet know the precise form the crack-up will take, but crack-up there always is. It may be physical, mental, spiritual, I don't know. But this I do know, Admiral Starr, the crew of the Ulysses has been pushed to the limit, and clear beyond."

"Very interesting, Commander." Starr's voice was dry, sceptical. "Very interesting indeed, and most instructive. Unfortunately, your theory, and it's only that, of course, is quite untenable."

Brooks eyed him steadily.

"That sir, is not even a matter of opinion."

"Nonsense, man, nonsense!" Starr's face was hard in anger. "It's a matter of fact. Your premises are completely false." Starr leaned forward, his forefinger punctuating every word. "This vast gulf you claim to lie between the convoys to Russia and normal operational work at sea, it just doesn't exist. Can you point out any one factor or condition present in these Northern waters which is not to be found somewhere else in the world? Can you, Commander Brooks?"

"No, sir." Brooks was quite unruffled. "But I can point out a frequently overlooked fact, that differences of degree and association can be much greater and have far more far-reaching effects than differences in kind. Let me explain what I mean.

"Fear can destroy a man. Let's admit it, fear is a natural thing. You get it in every theatre of war, but nowhere, I suggest, so intense, so continual as in the Arctic convoys.