It took a second for me to realize what it was. The false nose. A laugh escaped me. Holmes shook his head when she turned to stare at me.

‘Madame, I can explain all that you see here,’ said Holmes.

‘Explain quickly.’ She caught me shifting my weight as I stealthily attempted to draw nearer. ‘Stop there, you. Or I will shoot Mr Holmes.’

Just then Mrs Hudson appeared in the doorway, brandishing a tennis racquet as a weapon. I had wondered where my racquet had gone. She stared at the three of us.

‘Mr Holmes, I heard the commotion. Put that gun away, young lady, unless you plan to shoot all three of us. And sit down, all of you.’ She glanced at the clutter. ‘If you can find a seat.’

No one moved. Mrs Hudson was full of surprises today. She advanced into the room, tennis racquet raised.

‘Sit, or I shall knock sense into all three of you!’

Madame Borelli did not seem inclined to shoot the eminently reasonable Mrs Hudson in cold blood. She wavered, then replaced the gun into her reticule and looked round for a seat. I removed a large box of what appeared to be human bones from an armchair and brushed off its dusty wool surface. Madame Borelli glanced down, gave it one more furious brush and sat.

‘Tea, then, in a few minutes. Meanwhile, behave yourselves,’ said Mrs Hudson. She gave our visitor her sternest look. ‘This is a civilized house.’

Some minutes later, we sat facing hot tea and ginger biscuits, a veneer of respectability floating above the sea of clutter. Madame Borelli had calmed herself to some degree. The summer shower had dropped the temperature, and a tepid, damp breeze wafted into the room with salubrious effect.

‘Now, Madame Borelli, you have come here on another matter, I perceive, and not merely to retrieve the pages you so kindly lent me,’ said Holmes in the soothing manner, absent of any sarcasm, which he used at times to great effect.

‘Yes, I come. But I am not sure you are what I need. I am not sure—’

‘Tell me what is troubling you. You did not wish to open your reticule when you located your husband’s pages. And you have been keeping it close to you for your entire visit. But as you drew your gun, I glimpsed—’

‘Yes, yes. I brought something.’

My attention turned to the tapestry bag with gold fringe, on a braided golden cord which hung around the lady’s neck and was fastened with a small gold clasp to the sash of her dress. Even at this moment, one hand rested protectively upon it.

She glanced down at it nervously, then looked at Holmes from under her heavy fringe of dark eyelashes.

‘It is true. You said when we met that you … you write for science journals. But you solve crimes. Scotland Yard man says amateur. Are you any good at this?’