“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.”
“And it works?”
“Oh, it works all right. I am quite certain that sperm which has been protected with glycerol and then frozen slowly will stay alive at minus one nine seven for as long as you like.”
“For a hundred years?”
“Absolutely, provided you keep it at minus one nine seven degrees.”
“And you could thaw it out after that time and it would fertilize a woman?”
“I’m quite sure of it. But having got that far I began to lose interest in the human aspect. I wanted to go a lot further. I had many more experiments to do. But one cannot experiment with men and women, not in the way I wanted to.”