'Chemistry?' I asked.
'A bit of chemistry,' he said. 'And a good deal of bio-chemistry. 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, etcetera. 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 -97deg Centigrade. But even that wasn't enough. At minus ninety-seven 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 -197deg 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 vaporizing? 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 for ever. A little topping up was required now and again, but that was all.'
'Not for ever, 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 vaporize. 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?'