‘You will tell him exactly how you have left me,’ said he. ‘You will convey the very impression which is in your own mind. A dying man—a dying and delirious man. Indeed I cannot think why the whole bed of the ocean is not one solid mass of oysters, so prolific the creatures seem. Ah, I am wandering! Strange how the brain controls the brain! What was I saying, Watson?’

‘My directions for Mr Culverton Smith.’

‘Ah yes, I remember. My life depends upon it. Plead with him, Watson. There is no good feeling between us. His nephew, Watson—I had suspicions of foul play and I allowed him to see it. The boy died horribly. He has a grudge against me. You will soften him, Watson. Beg him, pray him, get him here by any means. He can save me—only he.’

‘I will bring him in a cab, if I have to carry him down to it.’

‘You will do nothing of the sort. You will persuade him to come. And then you will return in front of him. Make any excuse so as not to come with him. Don’t forget, Watson. You won’t fail me. You never did fail me. No doubt there are natural enemies which limit the increase of the creatures. You and I, Watson, we have done our part. Shall the world then be overrun by oysters. No, no, horrible! You’ll convey all that is in your mind.’

I left him full of the image of this magnificent intellect babbling like a foolish child. He had handed me the key and with a happy thought I took it with me lest he should lock himself in. Mrs Hudson was waiting trembling and weeping in the passage. Behind me as I passed from the flat I heard Holmes’s high thin voice in some delirious chant. Below as I stood whistling for a cab a man came on me through the fog.

‘How is Mr Holmes, sir?’ he asked.

It was an old acquaintance, Inspector Morton of Scotland Yard, dressed in unofficial tweeds.

‘He is very ill,’ I answered.

He looked at me in a most singular fashion. Had it not been too fiendish I could have imagined that the gleam of the fanlight showed exultation in his face.

‘I heard some rumour of it,’ said he. The cab had driven up and I left him.

Lower Burke Street proved to be a line of fine houses lying in the vague borderland between Notting Hill and Kensington. The particular one at which my cabman pulled up had an air of smug and demure respectability in its old-fashioned iron railings, its massive folding-door and its shining brasswork. All was in keeping with a solemn butler who appeared framed in the pink radiance of a tinted electric light behind him.

‘Yes, Mr Culverton Smith is in. Dr Watson! Very good, sir, I will take up your card.’

My humble name and title did not appear to impress Mr Culverton Smith. Through the half-open door I heard a high, petulant, penetrating voice.

‘Who is this person? What does he want? Dear me, Staples, how often have I said that I am not to be disturbed in my hours of study!’

There came a gentle flow of soothing explanation from the butler.

‘Well I won’t see him, Staples. I can’t have my work interrupted like this. I am not at home. Say so. Tell him to come in the morning if he really must see me.’

Again the gentle murmur.