'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 straight away to minus one nine seven degrees.'
'So you cool d 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 y
ou 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.'
'How did you want to experiment?'
'I wanted to find out how much sperm wastage there was in a single ejaculation.'
'I'm not with you. What d'you mean by sperm wastage?'
'The average ejaculation from a large animal such as a bull or a horse produces five ccs of semen. Each cc contains one thousand million separate spermatozoa. This means five thousand million sperm altogether.'
'Not five thousand million! Not in one go!'
'That's what I said.'
'It's unbelievable.'
'It's true.'
'How much does a human produce?'
'About half that. About two ccs and two thousand million.'
'You mean to tell me,' I said, 'that every time I pleasure a young lady, I shoot into her two thousand million spermatozoa?'
'Absolutely.'
'All squiggling and squirming and thrashing about?'
'Of course.'
'No wonder it gives her a charge,' I said.
A. R. Woresley was not interested in that aspect. 'The point is this,' he said. 'A bull, for example, definitely does not need five thousand million spermatozoa in order to achieve fertilization with a cow. Ultimately, he needs only a single sperm. But in order to make sure of hitting the target, he has to use a few million at least. But how many million? That was my next question.'
'Why?' I asked.
'Because, my dear fellow, I wanted to find out just how many females, whether they were cows, mares, humans or whatever, could ultimately be fertilized by a single ejaculation. I was assuming, of course, that all those millions of sperm could be divided up and shared among them. Do you see what I'm driving at?'