“Don’t often taste stuff like this,” he said. He was very comfortable in an old armchair with his pipe lit and a glass of port in his hand. What a thoroughly decent man he was, I thought. And what a terribly dull life he leads. I decided to liven things up a bit by telling him about my time in Paris six years before in 1913 when I had made one hundred thousand pounds out of Blister Beetle pills. I started at the beginning. Very quickly I got caught up in the fun of story-telling. I remembered everything, but in deference to my tutor, I left out the more salacious details. It took me nearly an hour to tell.

A. R. Woresley was enraptured by the whole escapade. “By gad, Cornelius!” he cried. “What a nerve you’ve got! What a splendid nerve! And now you are a very wealthy young man!”

“Not wealthy enough,” I said. “I want to make a million pounds before I’m thirty.”

“And I believe you will,” he said. “I believe you will. You have a flair for the outrageous. You have a nose for the successful stunt. You have the courage to act swiftly. And what’s more, you are totally unscrupulous. In other words, you have all the qualities of the nouveau riche millionaire.”

“Thank you,” I said.

“Yes, but how many boys of seventeen would have gone all the way out to Khartoum on their own to look for a powder that might not even have existed? Precious few.”

“I wasn’t going to miss a chance like that,” I said.

“You have a great flair, Cornelius. A very great flair. I am envious of you.”

We sat there drinking our port. I was enjoying a small Havana cigar. I had offered one to my host but he preferred his stinking pipe. That pipe of his made more smoke than any other pipe I had ever seen. It was like a miniature warship laying a smokescreen in front of his face. And behind the smokescreen, A. R. Woresley was brooding on my Paris story. He kept snorting and grunting and mumbling things like “Remarkable exploit! . . . What a nerve! . . . What panache! . . . Good chemistry, too, making those pills.”

Then there was silence. The smoke billowed around his head. The glass of port disappeared through the smokescreen as he put it to his lips. Then it reappeared, empty. I had talked enough, so I kept my peace.

“Well, Cornelius,” A. R. Woresley said at last. “You have just given me your confidence. Perhaps I had better give you mine in return.”

He paused. I waited. What’s coming, I wondered.

“You see,” he said. “I myself have also had a little bit of a coup in the last few years.”

“You have?”

“I’m going to write a paper on it when I get the time. And I might even be successful in getting it published.”

“Chemistry?” I asked.

“A bit of chemistry,” he said. “And a good deal of biochemistry. It’s a mixture.”

“I’d love to hear about it.”

“Would you really?” He was longing to tell it.

“Of course.” I poured him another glass of port. “You’ve got plenty of time,” I said, “because we’re going to finish this bottle tonight.”

“Good,” he said. Then he began his story.

“Exactly fourteen years ago,” he said, “in the winter of 1905, I observed a goldfish frozen solid in the ice in my garden pond. Nine days later there was a thaw. The ice melted and the goldfish swam away, apparently none the worse. That set me thinking. A fish is cold-blooded. So what other forms of cold-blooded life could be preserved at low temperatures? Quite a few, I guessed. And from there, I began speculating about preserving bloodless life at low temperatures. By bloodless I mean bacteria, et cetera. Then I said to myself, ‘Who wants to preserve bacteria? Not me.’ So then I asked myself another question. ‘What living organism above all others would you like to see kept alive for very long periods?’ And the answer came back, spermatozoa!”

“Why spermatozoa?” I asked.

“I’m not quite sure why,” he said, “especially as I’m a chemist, not a bio man. But I had a feeling that somehow it would be a valuable contribution. So I started my experiments.”

“What with?” I asked.

“With sperm, of course. Living sperm.”

“Whose?”

“My own.”

In the little silence that followed, I felt a twinge of embarrassment. Whenever someone tells me he has done something, no matter what it is, I simply cannot help conjuring up a vivid picture of the scene. It’s only a flash, but it always happens and I was doing it now. I was looking at scruffy old A. R. Woresley in his lab as he did what he had to do for the sake of his experiments, and I felt embarrassed.

“In the cause of science everything is permissible,” he said, sensing my discomfort.

“Oh, I agree. I absolutely agree.”

“I worked alone,” he said, “and mostly late at night. Nobody knew what I was up to.”

His face disappeared again behind the smokescreen, then swam back into view.

“I won’t recite the hundreds of failed experiments I did,” he said. “I shall speak instead of my successes. I think you may find them interesting. For example, the first important thing I discovered was that exceedingly low temperatures were required to keep spermatozoa alive for any length of time. I kept freezing the semen to lower and still lower temperatures, and with each lowering of the temp I got a longer and longer life span. By using solid carbon dioxide, I was able to freeze my semen down to —97° Centigrade. But even that wasn’t enough. At minus ninetyseven the sperm lived for about a month but no more. ‘I must go lower,’ I told myself. But how could I do that? Then I hit upon a way to freeze the stuff all the way down to —197° Centigrade.”

“Impossible,” I said.

“What do you think I used?”

“I haven’t the foggiest.”

“I used liquid nitrogen. That did it.”

“But liquid nitrogen is tremendously volatile,” I said. “How could you prevent it from vapourizing? What did you store it in?”

“I devised special containers,” he said. “Very strong and rather elaborate vacuum flasks. In these, the nitrogen remained liquid at minus one nine seven degrees virtually forever. A little topping up was required now and again, but that was all.”

“Not forever, surely.”

“Oh, yes,” he said. “You are forgetting that nitrogen is a gas. If you liquefy a gas, it will stay liquid for a thousand years if you don’t allow it to vapourize. And you do this simply by making sure that the flask is completely sealed and efficiently insulated.”

“I see. And the sperm stayed alive?”

“Yes and no,” he said. “They stayed alive long enough to tell me I’d got the right temperature. But they did not stay alive indefinitely. There was still something wrong. I pondered this and in the end I decided that what the sperm needed was some sort of a buffer, an overcoat if you like, to cushion them from the intense cold. And after experimenting with about eighty different substances, I at last hit on the perfect one.”

“What was it?”

“Glycerol.”

“Just plain glycerol?”

“Yes. But even that didn’t work at first. It didn’t work properly until I also discovered that the cooling process must be done very gradually. Spermatozoa are delicate little fellows. They don’t like shocks. You cause them distress if you subject them straightaway to minus one nine seven degrees.”

“So you cooled them gradually?”

“Exactly. Here is what you must do. You mix the sperm with the glycerol and put it in a small rubber container. A test tube is no good. It would crack at low temperatures. And by the way, you must do all this as soon as the sperm has been obtained. You must hurry. You cannot hang about or it will die. So first you put your precious package on ordinary ice to reduce the temperature to freezing point. Next, you put it into nitrogen vapour to freeze it deeper. Finally you pop it into the deepest freeze of all, liquid nitrogen. It’s a step by step process. You acclimatize the sperm gradually to coldness.”