Undaunted, I held on to the course I had marked out for myself when I started. Turning to the woman, as the train once again steamed off, I said with ironical politeness: “I must really apologise for the scepticism with which I treated you. I see, now, that you have two assistants from Broadmoor, but why don’t they wear Broadmoor uniforms?”

“They do,” she cried, and then she stopped and bit her lip. All at once she realised she had fallen into the pit I had dug so carelessly in front of her.

“Oh no, indeed, they do not,” I answered sweetly. “The uniforms which these women have on are only worn by nurses at Guy’s Hospital. The fact is, I have been often to Broadmoor myself, and I know the nurses there wear a totally different garb.” And I shot a glance out of the corner of my eyes at the pseudo-nurses themselves. One had flushed crimson, the other had gone deathly white, and was playing nervously with her pocket-handkerchief. They were impostors, I am certain.

The woman in black, however, rose with magnificent impudence to the occasion. “You, sir,” she said, “have been good enough to brand me with falsehood, and I have borne it without a murmur, striving only to prove to you, in the discharge of my duty, that I spoke fairly and truthfully. Now, however, you go too far when you attack my assistants. I repeat they are dressed properly, and I say that your statement that you have been often in our asylum, is so much fudge. Only doctors and police and inspectors from the Home Office go there as a regular rule.”

I waited for a moment before I answered, like a clever actor pauses before he puts in his most effective point.

“You are impetuous, madam,” I said, taking out my snuff-box with studied deliberation and pretending to take a pinch; “very impetuous. You ought to have asked who I was before you branded me, too, as an impostor. As a matter of fact, I do belong to the police. Here is my card.” And I quietly produced a card of Detective-Inspector Naylor’s which I happened to have in my waistcoat pocket.

The effect of my act was almost magical. The woman in front of me started violently and shivered. Then with a great effort she recovered herself and gave me another look of defiance. “I see,” she said, taking the piece of cardboard I handed to her with apparent carelessness. “I suppose you have been sent to look after Miss Velasquon by some friend of hers who does not know her real identity or crimes. It’s a pity, a great pity, for you will have your journey wasted. The patient, of course, is now in our care, and must go with us.”

“I don’t know so much about that,” I returned, although I admit I was startled with the daring and resource which this woman was showing, and which proved that she was up to every trick and turn and corner of those wretched lunacy laws of ours. “Do you mind showing me the authority under which you are acting?”

“Not at all,” she said in her most patronising and offensive tones, and feeling in a reticule that depended from her waist she produced this strange communication:

By Royal Authority.