‘He does know who pays your salary. Professor. He also knows who used to pay your daughter’s salary. Now, what about these results?’

‘They’re not definite, by any means. Only conjecture, based on the broad outlines of what we’ve been able to discover so far.’

‘In other words, you’re not prepared to stand by what you say?’

‘In other words, Peter, they’re the best that scrupulous and conscientious scientists can do when they’re put under pressure by a politician whose motives are mainly financial.’

Peter Kaiser sighed. ‘All right, Professor. You can spare me the puritanical rhetoric. What have you managed to conjecture so far?’

‘The samples we were sent by Dr Benson in Kansas have almost certainly been affected by a species of crop virus. The virus has been isolated under the electron microscope, and although we’re not sure exactly what it is, or where it comes from, there isn’t any doubt that it’s extremely active and extremely dangerous to cereal crops. It can spread as quickly as the most virulent of human diseases, and we’re surprised that it didn’t sweep through the wheatfields in Kansas more quickly.’

‘You don’t know how it originated? Whether it was natural or not?’ asked Peter.

Professor Protter hummed for a moment in uncertainty. ‘I’d hate to commit myself,’ he said, ‘but several of the wheat samples from Kansas had traces of some thin gelatinous substance on them – partly decomposed. Professor Gulaski has been running several tests on it, and he thinks it could be some kind of base material in which the virus was carried, and sprayed on to the crops. He’s only guessing, of course, but one of his experiments indicates that the substance slowly breaks down under the influence of ultra-violet light.’

‘What are you trying to suggest?’ asked Peter. ‘This virus was sprayed on to the crops on purpose?’

‘That’s a remote possibility, yes,’ Professor Protter told him. ‘Depending on how slowly the base substance was designed to deteriorate, it could have been sprayed sometime during the spring, when the first shoots of the wheat were coming up. Whoever did it could have easily prepared the gelatinous base according to the average number of hours of sunlight expected in Kansas, so that when the wheat was ripe, the virus broke out. It wouldn’t even have been necessary to spray every farm at the same time to have the virus break out simultaneously. All they had to do was alter the composition of the gelatine to break down more quickly, or more slowly, or whatever they wanted. Anyone with a reasonably expert knowledge of virology and the preparation of photographic emulsions could have done it.’

Peter sat back in his seat. ‘You know what this means, don’t you? You know what you’re saying?’