Then Marvin lapsed into adolescent incoherence. But something of his feelings had come through the wild torrent of his words, and his friend nodded sagely.

'Marvin,' he said softly, 'I read you five by five, honest to Sam I do. But gee, even interplanetary travel costs fortunes. And interstellar stuff is just plain impossible.'

'It's all possible,' Marvin said, 'if you use Mindswap.'

'Marvin! You can't mean that!' His friend was too shocked to avoid the exclamation.

'I can!' Marvin said. 'And by the Christo malherido, I'm going to!'

That shocked them both. Marvin hardly ever used bad language, and his friend could see the considerable stress he was under to use such an expression, even though coded. And Marvin, having said what he had said, recognized the implacable nature of his resolve. And having expressed it, he found it less frightening to contemplate the next step, that of doing something about it.

'But you can't,' Billy said. 'Mindswap is – well, it's dirty!'

' "Dirty he who dirty thinks, Cabrón." '

'No, seriously. You don't want some sand-grubbing old Martian inside your head? Moving your legs and arms, looking out of your eyes, touching you, and maybe even-'

Marvin cut him off before he said something really bad. 'Mira,' he said, 'recuerda que I'll be in his body, on Mars, so he'll be having the same embarrassments.'

'Martians haven't got no sense of embarrassment,' Billy said.

'That's just not true,' Marvin said. Although younger, he was in many ways more mature than his friend. He had been an apt student in Comparative Interstellar Ethics. And his intense desire to travel rendered him less provincial in his attitudes, more prepared to see the other creature's point of view, than his friend. From the age of twelve, when he had learned how to read, Marvin had studied the manners and modes of many different races in the galaxy.