I say, Watson,' he whispered, 'would you be afraid to sleep in the same room as...

I say, Watson,' he whispered, 'would you be afraid to sleep in the same room as a lunatic, a man with softening of the brain, an idiot whose mind has lost its grip?'
'Not in the least,' I answered in astonishment.
'Ah, that's lucky,' he said, and not another word would he utter that night.